Lina, Lion, Rhasta, Sven, VS
4 stun (3 easy AOE stun - lino, lina sven)
high spell damage early game (lina and lion ulti)
Sven and vs can be good at mid-game (with item)
Even without item, sven ulti and Rhasta ulti can push very fast.
With 1 or 2 arcane ring and perhaps 1 mekasm, should be able to end the game very fast

Weakness - late game will lose, especially when enemy got bkb.