You know, after reading through and playing around with a holy paladin on the Mists of Pandaria beta, it looks like paladins didn't get a ton groundbreaking class changes. In a way, though, that's a good thing! You still get to keep the same style of play, except you have a few new spells and abilities to really augment your healing even further. You don't even have to learn any new playstyles.
If you're an awesome healer now, then you should have no problems moving into the next expansion at all. The additional AoE helpers are a bonus. Even though Holy Radiance is awesome, it'd be nice to have a few other AoE healing spells for a change.