Maybe a solution would be to have character DLC (Characters that you pay to unlock) and a secondary way to unlock them without paying (A LENGTHY GRIND…like those 999999(?) pricetags some characters had during the CTT). It’s what other MOBAs like LoL does.
I guess as long as there is a way to unlock it for free, ragardless of how “fast” or “practical” it may be, a player can’t whine and complain about how it is “Pay to Win”.
I personally don’t see an issue with having to pay for additional characters since you’re not just paying for a “bigger pool draft”, you’re paying for a brand new Co-op and Solo experience as well.
Just because a game has a tantalizing MOBA-esque aspect to its gameplay does not exclusively make it a MOBA.
