Momentum + Zealot...hmm...my first thought would be that you'd have to have a little luck on your side to pull the two cards at the right opportunity, unless of course the deck were geared that way. Toss in Sundial for fun. Good point.
Immunity to crowd control, how to get around it? Let's see, some immediate ideas:
1) "Does not attack if opponent has no creatures in play."
2) "None of your other creatures attack if Zealot/Paladin is in play."
3) "You may not target Zealot/Paladin."
4) "Absorb X
each turn."
5) ...or even "Zealot/Paladin is unaffected by Momentum." Ugly, but it works.
Funny how once righteousness gains momentum it's almost impossible to deal with