I think it is perfectly reasonable for a group of players to require voice chat for their pug. If you have absolutely no access to voice chat, then you shouldn't expect to get in that pug.
Before my static came together, we we're pugging 1-3 people in coil every week. We even tried a few people who didn't have voice chat, and it was awful. It was always the same story everytime. "I don't need voice i've done every fight up until turn 5, I know them all" *player dies within minutes of each fight* "I'm lagging soooooooo bad" - yeah right... suuuuuure.
We've had 2 summoners we've pugged for turn 4 with no voice chat. Both times we tell them don't attack the knight... phase 2 they're dead with 2 seconds from... can you guess it?
Yeah, no more... We've refused to take people who can't manage to get voice chat. If you have absolutely no access to voice chat at all, find access or don't run with those pugs.