so anyways, the real reason.....
The whole crucifiction chain of events is inextricably tied to Passover. It just doesn't happen that way without the Passover meal, who is allowed to kill whom when, stuff like that.
Passover is the first full moon in the month of Nissan. ( they used to do it the first full moon of Datsun). In 325, the Catholic church was asserting itself about "We're not Jews, stop saying that!", so they decided on the first full moon of spring.. Sometimes those moons are the same, so it all lines up, and the Easter bunny has to make sure people know he's a bunny, not a lamb. That could be disastrous.
side note: the change in the Easter date was at a time when Constantine ruled, the Church was quite accepted, there was no need anymore to hide behind pagan celebrations by then.