I like the concept so far. I am not blown away by it yet for some of the reasons already cited, i.e. cumbersome data disk equipping, feats limiting toons for use, and slow game play due to limited energy.
I am probably alone in this next thought but I am not fan of the zone ability modifiers. I know we get data disks to counter this, but I would rather plan for battles with toons with their known abilities as is. I would like to use the data disks to allow me to use some of my underpowered or little used toons, vs combining with my best toons to beat known toons with uncommon power buffs.
The other thing is I do not like how the beginning of the ladder contains opponents that are relic level yet are really easy to beat with equivalent relic'd toons. like they are almost relic level in name only, but than if I use lower level toons against them, the lower level toons get wiped out like they are facing a relic team that is not relic level in name only. Just seems to be off to me. What ends up happening is I use the same 3 or 4 teams throughout the entire ladder and makes it seem like a chore more than fun to get to the final battle.
Admittedly, I am finding this new mode to be a bit of an afterthought in my gameplay and i have forgotten it is even there on more than a few occasions.