Depends on where your time limit is. In Fleet and Squad arena, upping the limit would allow people to lock a spot for 50 minutes without paying to refresh. Each refresh lets you then lock the spot another 50 minutes. It would render the ladder immobile.
GA? you have 24 hours to fight it. Not sure what a time limit there does really. Unless they want to keep you from paper cutting someone to death. If you need that long to decide what your next move is going to be, though, you need to get quicker. Sometimes, though, you just pick a bad match up and the time isn't enough. It's part of the events. Make sure you get a team that won't time out say you don't take a defeat for it. In GA it's one of those things that costs you a few points that can be the difference between winning/losing. I'd rather lose that way than having it be a tie that goes to who has the highest GP which i really don't like, though that's exceedingly rare these days.