I've never played a paladin beyond level 20, but I intend to play a holy paladin Legion, and use my boost on one.
So, I'll boost to 100 as holy and level as holy. Sounds viable honestly. Then, as my ilvl increases, I'll go solo mop raids as holy. Why do it as holy? Because I flippin want to. And for xmogs. Of course I'll play to the maximums in a group/raid environment and provide the best healing I can, but when its solo or random bg time? I'm flip-flopping talents and messin up some randoms/bosses. (hopefully they keep talents as a just swap and go thing).
Who else is going to stretch their holy muscles and be a combatant instead of "just" a healer?
(On a side note: Judgment tier set>all)