You only get your base attack bonus, not any strength bonuses, when you release a dancing weapon, correct?
Strict reading of the rules says that it's just BAB for attacking, and the only feats/strength/etc that would apply is when it is being targeted by a maneuver or effect that targets items.
Meaning, if you try and disarm someone of their dancing weapon, it's treated as being held by that person and it would be "defended" as if being held. Same with being hit with a fireball and failing the save, or a targetted disintigrate, etc.
That is the strictest reading of the rules though. For ease of play (and because I've never actually paid attention), anytime a dancing weapon came up, it used the same attack bonuses and such as it had when in hand.
Whatever speeds up play in my books. It's a +4 ability already... a person could go for +3d6 damage and something extra (or +5d6+2 against a particular bane creature) with that same +4. You give up a lot for 4 rounds of extra attacks.