Problem 1 - SLOW: I hope the 'slow' part will be fixed too. Really, 10mins in survival is already boring but at least you know how much time it will take, but 10 waves on defense is really too much, counting all the bugged AI Path and stucked enemies inside objects it takes FOREVER. So I generally just skip a lot of mode waiting better and faster one.
Problem 2 - BOREDOM: Arbitrations aren't even so much hard (excluding bugs and kamikaze objectives), they are only time intensive and boring, pretty much a waiting game multiplied by two. I would like to see something harder (so less boring) but faster, if it is possible.
Problem 3 - DROP: I think that the more you play (and the harder it gets) you should be rewarded with better drop.
And another thing. Any way to add a passive to Inaros in Arbitration? Maybe even 'more hp' or 'less of those things needed to revive him', because It's just sad to see a frame with a passive disabled. And I don't even play Inaros.