Thank you for Tahm Kench
TL;DR - I haven't even been able to play him personally, but the games of mine that he's been in (even on either side) have been an absolute blast.
A brief summary of two super fun moments without boring you all with the play by plays of those games.
1st: The game had dragged into 50 mins, we had broken into their base but just couldn't bring about "winter eternal" ;). Finally we try something of a "Hail Mary". Our ez had been farming most of the game by this point [had 400+cs], so we simply tell him to "get caught out". He does so rather impressively, luring 4 of their team into a chase into gods know where. Me (Riven) and Kench take the Croissant Cruise into their base and backdoor.
2nd: A fight breaks out in the jungle, I barely make it away from the initial carnage and the fight progresses into that "scour the immediate area to kill what's left" state. Threshes the world over were gnawing at my ankles just waiting for my soul to drop by this point. And TK flashes over the wall (from wherever the heck he'd been before), eats me, scurries into the bush with me, spits me out, then we ult to safety.
I started in season 3, so I don't know if there were other champs like this upon release. But TK has been, in my experience, the most fun champ I've played with simply by his being in the game. Keeping in mind I haven't even played him yet. Good on ya Rito.