Holy Paladin + 4 Frost DKs Arena Season 9 week 2

[Mercbeast]

Horde = Blood Elf (Instant-cast Silence, off of the GCD)
Alliance = Human (Free Trinket, 2/3 min CD)

If you want to be mechanically the best.
Not saying others will not work exceptionally well, but hard to beat those racials:

I think Draenei have to be in consideration now too, specifically for multiboxers. Gift of the Naaru now/will scale to 20% of the targets HP and it stacks.

[Mokoi]

Gift of the naruu would be nice sometimes, maybe a button to bubble on your healer and naruu them so u can focus on dk healing more.. Good idea