Entropy, what youre talking about is really a very simple issue, youre looking at movement in one of if not the most complex sport from a human movement perspective on the planet. You can take athletes that are insanely fast, explosive, strong, whatever, and if they havent played an adequate amount of basketball, they will look silly when moving in bball situations and under those specific conditions.
If you take a good basketball player, and have him try and run a 100m sprint, he will again look awkward if hes not practiced in sprinting, especially when comparing him with good sprinters, and even though he will lose horribly, he wont look "as awkward" as the sprinter who never plays basketball does on the court. You can carry this to many other sports, the bball guys move "better" in most cases when taken out of their own environment, than most other types of athletes. This is strictly from a coordination, fluidity of movement criteria, and its easy to see why, there are so many different movements required in so many different directions, angles, and speeds in their home sport.
The game of basketball is in itself great coordination work for many different sports, its very possible to be a slow sprinter, non explosive leaper, and move very well on the court when practiced enough. There is so much going on from a footwork standpoint that it carries over to that aspect much more than the reverse is true, ie. football carrying over to bball. The easiest way to get more "fluid" and at ease with moving that way is to do those movements over and over. Drill the moves you want to work on in isolation, then practice them in pick up games until its second nature.