For Return in particular it does make sense to compare it to 1 and 2, since Return seems to be picking the series up where Gilbert left it and ignoring what others did since then.
(For what it's worth, I remember Curse causing some controversy when it came out, because of that shift to the toon style from the original pixel aesthetic.)
All indications are that while the game picks up threads from MI2 and starts at the end of MI2, the bulk of the game may happen after Curse and even Tales. Ron has said multiple times that "it's all canon" and about the only things that he's acknowledged are kind of ret-conned around are some things that occurred in Escape, which even Tales partly ignored.
We don't have much details yet on how exactly it fits into the canon as the game isn't out yet, but Ron has kept pointing out that Return isn't "MI3a" like he originally grumped an idea about, but a post-Tales Monkey Island game in just about all senses.
Given Murray's involvement in the trailers to date, I think comparing the art style to Curse is more accurate, personally, and I think there's a loving conversation there. I like what I've seen of the art style so far. (But also I like Double Fine's "house style" and this clearly has DNA ties to that, too.)
(For what it's worth, I remember Curse causing some controversy when it came out, because of that shift to the toon style from the original pixel aesthetic.)