I quite like the Timer. I do dungeons as my primary method of leveling a new class.

I feel that without that timer, people just wouldn't try hard enough to succeed.
I still remember spending 5 hours in Blackrock Depths in WoW back in vanilla because the Tank kept AFKing and getting himself lost. Sunken Temple was another that could take forever due to people getting lost.

if we did not have the timer, people wouldn't care about wiping 100 times on a bad boss, because there is no punishment for doing so, which can lead to spending many hours in a dungeon and getting nowhere.