It seems like a pretty far cry from Persona 3 and 4 as well. Pretty much the only thing it has in common with P4 is that they both have upbeat openings. That's kinda it. P3's tone in both the game and it's opening are way different than this. I think they're just making a pretty uninspired anime game with SMT and FE names. Nothing about the game screams Persona either, because honestly if it felt like Persona and Fire Emblem mixed together id still be somewhat excited. It literally feels like it's own thing entirely.
Also you can't blame a game for not being another Nocturne yo, that's setting the bar way too high.
Well, the Persona derivative elements thus far imo:
-Emphasis on a "school life" setting
-Seems to mix a "normal" and "other" world
-Characters summon
stands familiars to fight for them, just FE people now.
-Upbeat opening (as you mentioned )and colorful "pop" imagery, though not nearly as well handled.
As for Nocturne, it's just a good measuring stick for a combination of outstanding gameplay and outstanding seting/atmosphere/story/aesthetics.
As I mentioned, I think it's fairly easy to make "okay" dungeon crawls, but it's difficult to make amazing ones. I have a similar attitude with shmups, where I try to look for things that are unique or outstanding and not just another Cave/Touhou clone. I think there are some really great dungeon crawls out there (Etrian Odyssey comes to mind), but as these guys have made a number of mistakes already, don't have much to their credit, and have failed to come up with a gameplay concept that mixes the appeal of either games, I'm not expecting that much skill.
I think "they wanted to make an srpg but couldn't pull it off" is a bullshit excuse for a lack of skill or ingenuity. If you're going to make a mash up, you either get the best of both worlds or you can the project.
Look at Mario RPG on Super Nes. What's Mario about? Jumping. Do you think the guys at Square back in the day thought it was good enough to just say "we can't think of a way to combine a platformer and an rpg, so let's just make a standard issue dungeon crawl with some Mario references and loosely translated mechanics". No. They incorporated platforming into the exploration. They incorporated jumping into the combat itself. In fact, they went so far as to make sure it wasn't even an aesthetic touch, letting you get bonuses for timimg your jumps and other abilities like a platformer. They actually went the extra mile to make sure it had the Mario/Platformer appeal in an rpg. I don't see anything that clever here.
Basically everything interesting about Fire Emblem comes from the fact that's it's an srpg. A very stripped down, fast paced, srpg. Weapon triangles and supports already have loose equivalents in other rpg's and the smt series itself. And it's the movement and spacing in FE that makes those mechanics interesting and unique in FE. Trying to make a FE cross over without movement is like trying to make a Mario game without jumping.