lots of good discussion.
I just have something else to add..
What if Lebron can't improve his free throws, his left, his footwork, etc? I've watched people toss stuff like that around for a long time.. but at some point, maybe we just have to deal with the fact that he can't make any significant improvements to these areas of his game. It may sound crazy to some, but we also have to realize Lebron is a freak athlete with insane power/strength. I imagine he got away with ALOT, in terms of over-utilizing his athleticism while he was developing as a child, teen, and young adult (and even in the NBA). These are very important years that you can't get back. If you look at someone like Curry, well, he absolutely has to be much better than Lebron at shooting free-throws, 3-ptrs, ball handling, etc. If he wasn't, he wouldn't even be a starter.
So the possibility that Lebron has reached a ceiling skill-wise is definitely there. And with that, he's managed to help get his teams to 6 straight finals, 7 total, various awards/accolades, 2 championships, gold medals, stat sheet monster, among the greatest stat-wise in several departments in HISTORY, etc.
I'm fairly certain he knows he's not ice-cold from the free-throw line to close out games.. How can you practice that? You can't.. that's just something you acquire over the years, or you just don't have it. It's very possible that he just DOESN'T have it. But he makes up for it in so many other ways. That has to be acknowledged.
Look at someone like Rodman.. he figured out exactly who he is. He's considered an all-time great. I'm sure we could go on and on about all of the things he could have improved in his game, but didn't; shooting, ball handling, free throws, etc. I'm sure he tried for a while, then realized it might be better to just hone-in on who he is and contribute in different ways. People rarely criticize him because they've realized who he is, a monster rebounder/defender/leader.
That reason above, is why I just don't understand many of the Lebron criticisms.. He's not Kobe, MJ, Magic etc.. He has his faults, but somehow he keeps winning. I think that needs to be respected as a skill in itself. He's a dominant force when he's out there; rebounding, assisting, scoring, leadership etc. He can dominate in any form.
Finally, again i'll go back to his athleticism.. How many times have we seen freak athletes do absolutely nothing in the nba, or never even make it to the nba. I'm sure most of us who have played basketball on the streets have seen people who are just freaky athletic but never do anything. Lebron could have been "that guy". He's worked on his game HARD in order to not be, that guy. He could have easily have never developed a jumper at all, or the court vision he has. He could have been obsessed with dunking/power and that's about it.

edit: for those who don't know about his h.s. football background: http://espn.go.com/nfl/news/story?id=5360552
In reality he's a two sport athlete.. He wisely chose basketball. People with his power don't usually have nearly the kind of finesse he has. He's a damn NFL Tight-end out there who can light it up from anywhere on the court.
Also, as far as his nickname.. I have no idea if he named himself "King James" or other people around him did.. It's fair to say it's just going to be his nickname, given it's one of the first things you think of when trying to create a nickname for someone with the last name "James", since for some reason we all know about a King named James.
And Kobe named himself the Black Mamba.... relax people.
I wouldn't say his ego is any bigger than MJ or Kobe.. MJ fought steve Kerr during a practice, got in numerous fights. Kobe got into several fights (chris childs lit him up), he was hated by many of his teammates and those around the league. How many fights has Lebron been in? Maybe that says alot about his personality (or how the NBA changed).. Maybe he just isn't as much of a KILLER as Kobe or MJ. I'd definitely say he isn't. He's this weird mix of scorer, assist-man, rebounder, freak athlete, great leader, etc.
Now if only Shaq had developed a Jumper and improved his free-throws............... 
pc! ;f
Great, great, great post.
Just wanted to add a few things.
First point about Lebrons athleticism. You did a great job articulating a myth that needs to die - that Lebron James is just a big beast. People need to realize that Lebron James is simply not THAT athletic. What I mean by this is he isn't who he is because he is big and strong. I play basketball with a guy at the gym who is 6'7 275 (former football player) and he is ok at pickup ball until a decent 6'4 or taller guy guards him. Could someone dominate basketball through sheer athleticism alone? Sure. I'm sure I could dominate without practice in the NBA if I had my athleticism but was scaled up to about 9 feet tall. Basketball is still a skill. Lebrons size would make me a beast at the high school level but I would have to put in some serious work to even be an ok d1 player even if I had that height... Lebrons gifts are not common but they are not so rare that he is the only guy in the world with them. Everyone who thinks that Lebron is just athleticism should look at Jimmy Grahm of the Seattle Seahawks. He is 6'7 260 and has NFL level speed and played basketball at the University of Miami. He is a beast football player. He basically has approximately Lebrons physical gifts and was an average college basketball player... That's what Lebron was born with - a body that would get him to come off the bench of play as a mediocre college basketball player even if he didn't put in much work on his game. Sure that's more than most of us are born with. And it's more than Steph curry was born with (Less than Shaq was born with though). But he has surpassed it by so much that it is really unfair to characterize him as just a physical force...
As far as your second point about improving weaknesses... You are right. We can't look at a player with deficiencies and claim the player is lazy for not improving them because you simply can't say that because one player has easily improved some facet of his game that so too could another... Individual variation is such that some things are really hard for some people and some things come easy to others...
However what we can do is two things... Look at how much better the player would be if he improved it - and use the evidence we have to make an educated guess about whether the players inability to improve is primarily from his laziness or from his individual variation.
Take Rodman. Would he have been better if he shot a higher percentage from the line? Yes. Everyone would. Steph curry would be better if he shot 96% instead of 92%. But how much better would Rodman have been? He didn't attack the basket or go to the line much... We can assume it would have helped but not much... It's like Peyton manning if he had worked more on his speed... If he ran a 5.1 40yd instead of a 5.8 40yd or whatever terrible time he ran... Those few times he had to scramble he would have been better but they were few and far between cause that wasn't his game...
Shaq on the other hand would have been far far far better if he could have shot just 65% rather than 50%. I forget the stats but I think he would have averaged something like 35 pts a game or something had he just shot slightly better from the line... Free throws are kind of the special case in basketball because everyone shoots them. You can say a player is better if he shoots 20% from three instead of 15% (because he certainly isn't worse) but it might make very little difference because he still shoots too low of a rate to justify his team wanting that shot at anytime except when the shot clock is expiring...
Now given that Shaq would have been much better at basketball if he could have shot free throws... Let's make an educated guess about how hard he worked at this skill? He filmed Kazaam in the offseason. He waited till season to get surgery because he "wanted to heal on company time". He said dumb things like "I make them when it counts". Now that's not proof he didn't work on it but my educated guess is that he was satisfied being really good and didn't feel the need to put in extra work to be even better and it pissed guys like Kobe off... This isn't to say that he could have gotten better if he practiced... It's just to say we will never know because I don't think he practiced his free throws as hard as he could have...
As far as Lebrons weaknesses. You make great points to refute a lot of Chris Ms claims. However I will admit I am somewhat swayed by Chris Ms free throw argument... After seeing kawai Leonard raise his percentage, seeing Magic Johnson raise it every year, seeing even Tim Duncan finally raise it after years of struggles I do find it a bit suspicious that Lebron hasn't raised it at all is troubling... The fact that he shot 75% as a rookie and 71 and 73% the last two years does not make sense to me... I mean we don't know. Maybe a hand injury that hasn't been reported... But you would expect a player fresh out of high school who simply hasn't gotten as many reps in to be able to improve his ft rate at least somewhat... I'm not saying he should shoot 90% but anything about 80% would be sufficient to convince me he does everything possible to make himself better...
Still. Go Lebron. I'm a Lebron fan and here is the moment I became a huge fan. Back when Instagram was in its infancy I was following Lebron at the height of his non-popularity when he had just joined the heat... He posted a picture of his wife with a caption that said something like "I love my beautiful queen". A commenter wrote "your the best player in the world but sorry bro your girl is about a 5".
Now most celebrities would do the smart thing and ignore the trolling of mean spirited fans like this. The most immature celebrities would engage the fan and say something mean back or try and ruin their life on social media (see Rihanna)... What did Lebron do?
He responded. With a sad face emoji. That's it. Maybe it doesn't strike the rest of people but I thought it was so brilliant. No engagement. No need to remind the fan that he is a loser and "I am Lebron James and have millions of dollars". Just the humanistic response to say with a single emoticon that "hey man I'm sorry you sad that it hurts my feelings cause it's mean." Brilliant.