How could there be any kind of exhaustion mechanic when you have effectively unlimited Long Rests. Probably they tried implementing exhaustion and then removed it when someone in playtesting got a headache when they had to think about stuff.

I would very much like some long lasting conditions. It's beyond stupid that diseases last 1 minute. Exhaustion falls in the same category but I think poisoning, diseases and other injuries are more important. First, long rests need to be made into a meaningful mechanic. The game can do without exhaustion, but Frenzy needs to be toned down for sure.