Actually, it's harder to control cities with christian temples. You get max 5% more order from the highest level christian temple (which you should never build in any event -- it's far too expensive). But you'll have 1% more pop growth, which only makes it more difficult to maintain order (higher squalor and higher garrison required).

I won my WRE VH/VH campaign in 375 AD, and every city, including Rome, was completely pagan.

In addition to the order benefits, moreover, pagan temples give better bonuses. +2 exp to troops is particularly nice.