Cho'gath's voice rework is going to hurt.
http://3.bp.blogspot.com/-2oZuvGeIgYc/VC5ezwjN0WI/AAAAAAAAaTA/Rs3u4bWNWOI/s1600/Chogath_Splash_0.jpg
I'm going to be really sad when they get around to redoing Cho'gath's voice. While it'll be good to have more lines, I think he's got a pretty strong VO right now.
More importantly, I think Cho'gath depends on the dialogue with a Summoner more than perhaps any other Champion. His VO is a lot of fun because he's taunting you and seething at you the entire time.
"You have stains upon your soul. … perfect!" "No, I do not live under a bed! FOOL!" "Summoner, your darkness beckons." "Afraid of the dark? Wise!" "Death is not the end to you, I have seen to it. For eternity, YOU ARE MINE!"
I really like the setup of you summoning this terrifying Void monster to the Fields, but starting to be corrupted by him as you exploit his power to win whatever dispute or political battle you're engaged in.
Sure, they'll probably find a way to keep him menacing in his new VO, but I like that subtler, creepier dynamic of him slowly corrupting his ostensible "captors".