Yeah doesn't seem that good, if you're playing control, you can't play a big minion+this at the same time unless emperor+coin or double turn emperor or something like that, and generally speaking you won't have big minions on the board already and have another turn to play this behind. Especially not 2, and if it's just one it's kinda like an expensive argent protector, I mean you can token if you want to spend your entire turn getting a 1/1 divine shield on top but... And it's not really like Paladin is hurting for lategame threats anyway(or any deck really) and this one isn't even that threatening on its own. And definitely looks too expensive for an aggro deck.
Not a bad card, just doesn't seem really useful for anything besides arena.
If it was 6mana 5/5, it probably would be better cause it could be played along Sylvanas or Cairne or something after an emperor cost reduction, and that'd be a really annoying board to clear.