My biggest deal with not playing a bard is that there is no room to make yourself a unique Bard, as every bard at a certain level will basically be the same. Fighters can customize themselves through feats, wizards and sorcerors define themselves through their schools and bloodlines, clerics domains, rangers preferred enemy/fighting style, barbarians with their rage powers, etc, etc, but Bards all get the EXACT same perform abilities at the same time, and they are forced to do mainly Sing or Intrument perform checks. I think it would be cool if they had a system similar to what the Barbarians have where a bard can choose their own "performance power" as they level so that a player can choose which path they want to take their bard, be it a Dancing Bard, Singing Bard, Intrument playing Bard, etc, etc. The basic Bardic Performance abilities like Countersong, Inspire Courage, and such could be automatically gained at certain levels, while the others could be chosen as a Bard advances. The whole point, as I said earlier, would be to make it so all Bards aren't mirror images of each other when they reach level 20.
I'm not terribly creative to propose a whole lot of specific performance powers, but some of the old Bardic Feats and Bardic Prestige Class abilities from the old 3.5 supplements like Complete Scoundrel could be made into Performance Powers. That way you could have bards specialize in dancing, evil performances, good performances, acting (spy stuff), etc, etc.
Let me know what you think and if you have some possible ideas.