I think like I said team trainings
Well you can train the whole team in some skills. If you could use your imagination, you could take the overall team training as keeping your players at the current level. The older players drop because they can't maintain that level even with team training. You can set the
extra training.
like how they brought in FT coaches for Shaq
That's the beauty of this training system. You are not limited in any skill, only potential and you can make absolutely anyone shoot like Dirk or RayRay from the free throw line. Shaq got special training, but he still could not make his FT's. Nomatter the hours you put on it. If you can't shoot, you just can't shoot.
why bother with 5 on 5?
That's easy, they took the basics. They had choises though. 3on3, 1on1, 5 fouls instead of 6 fouls etc. They just added a twist to training, to make the game interesting. Every player constantly improving isn't realistic aswell and it would be really boring. Here you can create your francise player from the scratch.
Imo they have made great choises with contract system and training.
Perhaps you could point out a more realistic online basketball game as good as BB? Or better yet, go create your own game and stop trying to ruin this one.