I’ll make this into its own post as I think it keeps getting swamped by all the other issues cropping up.
I am a lvl 140 player and have invested in a team that could handle challenges on Warlord IV, which is where my (current) soul-grind is taking place. Now that 1.0.9 has introduced level requirements for the different difficulties, my soul grind is forcefully replaced by a level grind - almost certainly not the intention.
I cannot imagine there’ll be that much difference between level 100 and anything higher, just more (ie different) teams fully setup. But at 100 you can easily have gotten one or a few legendaries and built one or two teams that are strong enough to do Warlord IV on.