I look at Yrel's kit in HotS and think it could make a great tank in LoL

Yes, more of me comparing HotS to LoL, but Blizzard has good designs with its heroes. Case in point is Yrel, the game's latest hero, who is a frontline tank whose abilities require charging to get the best results. This allows her lots of power, but requires deliberate commitment and planning with her abilities to get the most out of them. Crowd controls or high mobility can all throw off her engages, but she makes up for that with how potent her abilities can be.

Galio sorta comes close to this with his own kit, but not quite to the same degree. But I'd personally love to see a charge-up tank in this game. The whole charge-up mechanics would allow for some really high power budget, especially since Flash can let you avoid most of the attacks.