Both mangas leaned heavily into their ecchi fan service early on to build a following, and then shifted focus more towards the cosplay side of things as the story progressed. But while Dress-Up Darling has seemingly abandoned all pretences of being a rom-com, and thus become an incredibly dull read as a result, 2.5D has never forgotten what it originally sold itself as. That's more than just remembering to keep up a supply of drawings of cute girls wearing cosplay outfits; it's maintaining a focus on character interactions and motivations, romantic development, and comedy.
If anything, 2.5D has got better as it has gone along. The art has been great from day one, but some of the drawings in more recent chapters have been truly stunning. As they've become more confident in both the manga itself and the readers familiarity with the characters, the author has really started to have fun with the format, introducing some great little recurring gags, 3rd (and possibly 4th?!) wall breaking, references to other media, and using different art styles to highlight the 2D vs 2.5D vs 3D themes of the story. A steady stream of new characters have been added, each of whom gets enough time for us to get a good feel for who that are and their motivations for wanting to cosplay.
That exploration of why the different characters want to cosplay is what really makes this manga shine. This isn't just a superficial vehicle for delivering fan service, it's a solid exploration of a subculture that I assume the author has a lot of love for, and those varying motives for cosplaying give us a cast of well rounded and interesting characters. So much so that they're all best-girl contenders, there really is no clear choice for who the male lead should end up with in the end.
The male lead is an interesting character in his own right too, who shows real growth as the story progresses. He's not just some self-insert blob devoid of personality, nor a Mary-Sue, nor an infuriating Kazuma type. Yes, the setup itself is about as unlikely as you'll find in any harem-esque manga, but at the same time it never feels out of place that all these pretty girls are hanging out with this diehard otaku, primarily because we've seen him do enough to earn the affections of each of them.
If you're not averse to some fan service then 2.5D Seduction is well worth reading. It delivers on all its promises, providing a read that is fun when it needs to be fun and meaningful when it needs to be meaningful. Hopefully the anime adaptation coming later this year will bring it the audience it deserves, and will pull it out of Dress-Up Darling's shadow.
