I will be very annoyed if the tadpole can't be promptly removed because Larian decided for me that I need fun powers, and that's all the tadpole is without any drawbacks.
With tadpoles being source/bhaalspawn essence I am willing to bet that we are stuck with them for the entire game. At the end of act1 we will learn what the tadpoles are really for, like we learned there is more to us being sorcce users in D:OS2. The rest of the game will follow from that.
Already in EA, if you use the tadpole enough times you become a mind-controllable True Soul
(The Absolute tries to control you on the bridge, nearly succeeds, and Shadowheart comes along with her d20-shaped Deus Ex Githyan-kina to save the day.) But logic and self-preservation aside, the player is incentivized to keep using the tadpole (not only for the powers but for easy conflict resolution & to get info on the team's supposed enemies). So I believe the game will push for illtihid wisdom checks to hook most players by the time of the 'grand reveal'.
Maybe a few players will be at 0 tadpole dreams, and they will get some sort of funny subverting expectations scene (like actually sitting down to eat Raphael's food) but for everyone else, I expect some grand climactic moment full of dramatic tension, painful choices, etcetc.
On topic: my favorite tadpole power is a tie between the knockback + dmg from the Underdark quest and the cleric's on death heal. It's a decent oh shit button, but would be even better if it scaled with level.
