I find the new announcer terrible, and I feel bad because I know you probably put a bit of effort into making was is essentially the voice and spirit of the game. The thing is, outside of maybe Katarina, the voices in game are very good. Nasus might be my favourite voice to date, and I remember thinking "Man I wish Nasus was the announcer" when i heard him and then the new announcer right after. I'm not sure exactly what rubs me the wrong way, but it's probably the distortion on the voice, it's just ridiculous. The new "destroyed an inhibitor" sounds almost mumbled as well. I enjoyed the variety of the old announcer. "Owned" was short and sweet, and drew my attention (to be honest, I didn't mind the original announcer in the first place.)
Like I said in a previous post, a calm, stern, slightly eccentric announcer would be more up my alley, akin to Team Fortress 2's.
I'm sure tweaks will continue to be made, or an option to maybe remove the announcer and replace the notifications with specific sounds will be implemented.