In fairness it does say on the power you cannot use other powers while active. But yes, something that huge should not be like a fine print footnote, that should be big bold letters at the top.

Honestly, I kind of love this idea. I realize there're bound to be problems and PvWhateverers screaming that it's overpowered and needs a nerfbat and Batflight-fanboiz screaming that it's underpowered and needs to be uberbuffed, but... this is honestly just a pretty cool idea. It affords some minor protection (face it- regeneration (and I'm guessing far less than the actual passive) is a very minor compensation for having all other powers locked) and does a bleed attack (I'd make it a close-range AoE- maybe 5-10 feet) as you switch back to biped form. It's thematic, it's cool, and it's not game-breaking that I can see.

Even better, make it a 1-2 point advantage: Vampire BATS!

Wouldnt be easier turn the bats into an "aura" and just fog the character, turning this power like another flavor flight travel?

Its basically that already your character doesn't go any where there just invisible and have a aura of bats.

I like this suggestion it would also look pretty cool I think.

The character model and skeleton are still there, just invisible. Back before they made it shut dark aura off on the become versions (bat flight, scarab tunneling, scarab flight), you could see the aura around the invisible body. It would react normally when you moved or triggered emotes, so the skeleton was all there.
All the power emanation points should still be on the skeleton, it not they can easily put them back. It really isn't that difficult. If they let it use powers normally it would just make your invisible body show for some of them, which is probably why they shut them off like they shut off dark aura showing up.

More people complaining about "balance"..

The power is working as intended and is in no way out of wack with any other travel power. They all are functionally the exact same.

Other flight based powers allow you to fight while you are flying. Why should we take a massive loss in an ability just for the graphic? It is not working as flight powers are intended, and it IS way out of whack with other flight based travel powers.

Even scarab flight allows you to attack and thats identical to (and cheaper to buy than) bat flight!

So why should bat flight be the ONLY flight power to have the extra disadvantage ?