Honestly 7.5/10 seems fair. It's fun but like you said there's barely any cum and/or difference from splatoon 2. I've enjoyed my time with it but it still really seems like it should've been DLC for Splatoon 2. There are 5 new maps and a handful (I don't know the actual number) of new weapons, but the fact I paid $60 for this is a little disappointing. Graphics are largely unchanged, majority of the maps are from previous games, and there are no new game modes aside from the 1v2 for splatfests.