Snowflake is a solid feat. Quite well designed, though I think it leaves you winded or fatigued or something afterwards. It'll either work very well with Barbarian Rage, with overlapping negatives, or it'll be terribad -- causing a wardancing, raging barbarian to go straight to exhausted for the next 8 hours.

If you're bent on making Battle Dancer work, I'd consider not only changing the bonus type (untyped would be the simplest fix), but change the value to be a bit more sliding scale. Perhaps +2 bonus, and an additional +1 for every 5 ranks in perform (+3 at 5 ranks, +4 at 10, +5 at 15 ranks, +6?! at 20) or some such. Change the progression to suit what you think is balanced, and remember he'll be stacking on Inspire Courage.