Pretty sure it happened the other way around, though.
If I'm not mistaken (my personal timeline/continuity can be pretty wonky
),
Doomsday Clock was already in the works before Bendis came to DC. Geoff Johns had already been holding the LoSH hostage for years at that point; couple that with the delays and what Bendis wanted to do with Superboy et al., and we end up with the dissatisfying mess we got. If Johns had been on his game, we'd have already had a Legion book on the stands (or at least in the works).
That vacuum allowed Bendis to jump in and say "Hey Dan! I have an idea that absolutely no one asked for!"