All that Clavileo needs is a consistent way of offing his own Vampires once they've attacked
The only thing this would actually solve is letting players know exactly which Prize Card they need to take when, and if, they are given the opportunity to do so
Cards such as Izoni, Thousand-Eyed, Charnel Troll, and Hatchery Spider are huge threats that benefit substantially from filling your graveyard with creatures
You can also pitch it to Chrome Mox, in order to ramp yourself into the mid-game
This design captures her role as a leader and protector, rewarding synergy with Allies while giving flexible board control
An abundance of removal spells in Constructed, and especially bounce out of the control decks, kept it down in Standard, but probably more than they should have