Well, Resplendent Angel isn't a must-remove threat until six mana; however I'm really theorizing at this point so ignore me.

As for Pelakka Wurm, I was thinking of it because you're running Revitalize. I presume that's because you have problems against aggro and need lifegain. Pelakka Wurm provides that lifegain. That said, it is a 7-mana card, and without the likes of Elvish Rejuvenator, it doesn't look like your deck can support it.

Revitalize gives me a couple useful tricks. Delaying aggro and providing me with an extra turn 2 options, especially if I'm holding up Seal Away.

And I would posit that Resplendent is must remove, because if I untap with it, I can protect it or combo off with it with Lyra.