I love the idea of a somewhat competitive system like the arena. It gives people something to work towards that is theoretically endless. However having to start all the way over at 0 after grinding out hours upon hours feels extremely bad. It essentially gates it to only people who don’t work or weekend warriors.
My suggestion is to have some sort of checkpoint system. POE has every node as a sort of checkpoint for Delve, Diablo III you just pick the level of the GR but it seems that EHG wants to go a different direction, which I can respect. So in that thread what if instead of having to grind and grind hundreds of waves if you leave or die you lose 50(100?) waves. that way you could still progress if you can only play after work during the week and not have to grind all the way back up.