I don't think fealty to the mana cost is too important; it's already white and a creature, why not change the mana cost too? That said, I kind of like the suggestion*. The interesting thing about it being 2W would be that it would be easier to splash, but you'd have to splash it with basic lands to not hose yourself. Although I think I'd still play (say) a Tundra rather than a Plains in a base blue deck to play this. You let one land stay tapped to tap down something close to their whole mana base. It seems like it would promote interesting deck-building decisions, whereas 1WW sort of confines it to a largely hypothetical "white weenie lock" archetype. Kor Sanctifiers indicates that a 2W 2/3 with a conditional ability can be fair.
* I also would have never suggested it myself, which is why I like having diverse voices in a forum, even when I usually disagree with them.
