Overall, I think it's a good expansion and Plarium did something good for one. (Credit is due where credit is deserved)
The only part I find difficult is that during each room, you're limited to certain champs, sort of like DT. That's cool and all and makes it challenging, but I've found that even just on normal mode. Bommel and a couple of other guys have been SUPER DIFFICULT. I just wish we could see it be slightly easier on normal mode compared to hard mode.
Overall, it seems pretty good so far, but only time will tell. I just wish that Plarium can also help with making the game less "grindy" in certain aspects as it's like having a full-time job to try and do a lot of the content still.