It may be that I've just missed it, but I'd really like to see is some way to see whether a mission has Exhaustion after it's already running. Sometimes I forget which followers I've assigned to which missions, and only some of them have Exhaustion. But so far I haven't seen a way to tell this after it's started. If I forget which ones I assigned to an Exhausting mission I have to just wait until after they get back to see whether a follower can run a mission again today.
(Not a complaint, just a suggestion for future improvement.) :-)
As it happens, exhaustion is going away in an upcoming build. The level 100 missions will feel much more like level 90-99 missions, although with longer mission times and slower repop rates than level-up missions have.