Still think it is a bad idea.
I prefer text trash talk mapstackers.  I don't want to have to listen to their weak ass responses. 

Its annoying to type strats.  Its hard enough to get people to follow you with voice, but now limit the pre-round to text only.

Its annoying when two friends on the same team talk on and on.  At least the when they are separated it gives some needed silence.

Things will get out of hand, people will be muted/kicked/banned, admin abuse threads may increase with accusations of favoritism, and heaven forbid a female gets on the mic. good grief.