Well, first off, that it will not be DnD mechanics is a huge plus for me.

That said, I didn't care for the mechanics in D:OS1 either because I found it to be extremely superficial and shallow, and especially that all you needed to do was to give every single one of your party members a specific set of spellcasting abilities and that was it. None of the other abilities, including especially marshal abilities, mattered by contrast. However, from all the interviews I have seen thus far with Swen, he seems to get this point as well, and seems to understand that mechanics is an area where they need to improve quite a bit over their past games. I fully expect it will be a classless system, because that's what fits their claim of wanting to build a game with maximum player agency. That translates into giving players the ability to be and do anything and everything within one character, as that's what most people interpret as having "agency" (whereas I certainly don't accept this). But I am willing to wait and see if Larian can successfully pull off a classless system where there is NOT just one optimal or "perfect" build.