Time wasting is the thing I hate most about football. And it's getting worse.
For Christ's sake, you don't need extra time. Just use a stopwatch. Stoppage in play? Time off. Ball out of play? Time off. Doing that removes most advantages to time wasting. And there is no random calculation required for how much extra time is awarded.
There's a bunch of studies that show the ball is in play on average about 55 minutes a game. And that is declining. So make it 30 minutes a half, and manage time properly like every other sport does.
The creeping up the sidelines for throw-ins pisses me off too. Advancing 5m or 10m seems to be no problem at all. Maybe the linesperson should spray some foam on the ground where the ball went out. And if you go past there, the other team gets the throw-in.