The duration time is fine.
If it was any longer your team would be put way behind. That sucks for you, but if the enemy team was halfway decent they would have exploited your time spent disconnected. This game is so unforgiving when it comes to leads, and a laner or jungler being absent is just as bad as feeding. They're getting free gold, levels, and tower damage. Then you're going to need to sit under your tower, and worse case scenario you could be watching them farm while they freeze the wave waiting for you to try to farm. If you're the jungler then you better believe the enemy jungler is going to be looking for you.
You can still remake the match after a death has occured in the game, so I don't know what you guys are talking about there. That was changed. The real problem I have with the remake system is that sometimes players initially connect, but then disconnect before you even leave the fountain. That denies players a chance to remake.
I have seen this occur on my team and other teams. It sucks.