Coach Jack Martin asks a great question regarding his own experience with balance acquisition following some minor knee surgery.
It's important to set our athlete's up for success. Begin where their strengths are, not their weaknesses. Find that athlete's envelope of function and work at the edges, with the goal of expanding that envelope. Be wary of these guys that insist on standing on unstable surfaces (bosu, tilt boards, dynadisks). It's very rare that in vivo the floor will be moving beneath you, except maybe if you surf or do boating. I'm not saying to avoid it, just saying it should not be the main focus of balance rehab. Teaching yourself to be still on an unstable object has little carryover to function.
If you are confused, take a look at this link to an article on balance by my GAIN buddy Steve Myrland. Steve takes his que on balance training from Bruce Lee's "The Art of Jeet Kune Do". On page 4 Steve gives a great synopsis of what a great balance progression should look like: