Nah I don't see time-wasting being an issue. Like I said, if they were to implement it they should only allow it to be used for big issues like disallowed goals, or goals that shouldn't have been allowed due to an offside or so on. It doesn't take long for a player to say, "we'd like to appeal", the referee to then inform the 4th official by microphone, then no more than 15-20 seconds to study footage, then a decision is made. Easy as pie. And like I said, there isn't even big issues and controversies every game, so it's not like it would ruin football like some people like to say.
The additional referees idea is bullshit. Use the goal-line technology to sort out the 'did it cross the line' issue.