I personally don't want to judge too much before actually trying it, but I'm a bit sad that such a short timer will mostly help hardcore people who can play 10+ hours a day to spam the dungeon and get the loot quickly. It's the same broken thinking that was behind surplus, which prevented casuals who could only focus on one class at the time to keep up.
A reasonable timer (from 12 to 36h) would have kept the players on their toes since failing it would actually mean something, and kept it balanced for every playstyles.
Anyway, we'll find out really soon !