Hobo Elf
Arcane
I'm not feeling it this time. As my nick suggest, I'm a big Nocturne fan. Strange Journey was great, not too far off Nocturne in fact. SMT IV has significant gameplay problems (see Nikaido posts) but also the game was getting more generic anime. That's a problem, it's a series that was doing mostly its own thing, while it was of course strongly influenced by anime.
Now Apocalypse feels more and more generic and seems to be getting more edgy: looks there's poodles of blood and loads of demons! There's also lots of demons with titties, what's not to love? Sure, the series was always about cheap horror with supernatural events and beings but it seems that it has become a joke of a joke now...
The series always was on a careful balance artistic and gameplay wise and it seems that newer games are trying their best to break that.
Your problem with the game is that it's an actual mainline SMT game instead of a Nocturne sequel. Nocturne is so far removed from SMT1 & 2 that it's weird they didn't make it into a spinoff. Dunno what your beef with SMT4's gameplay was (the mechanics were superb, the best the series has seen yet, but the balance was off and so the game became easier for it) but all the Japanese hardcore SMT fans universally agree that SMT: Final/Apocalypse not only fixed everything what was wrong with SMT4, but it is considered to be the best mainline SMT game. Japan loves it even more than Nocturne.
Is that truly the case? I wrote off apocalypse as I thought it was just more of SMT4. I guess I will keep my eye out for it.
Bosses have been buffed to better match the QoL improvements that made SMT4 easier. The Smirk system has been refined; spells now have alternative modes that go off if you cast them with the Smirk. Hamaon and Mudoon, for example, are not Light / Dark based OHKO spells anymore, but deal damage now. If you cast them with the Smirk status they'll work as the usual OHKO spells. This means that you can't get lololo insta killed during an unlucky ambush. You can get OHKO'd if you screw up and give Smirk to the enemy. Feels a lot more tactical this way. The art of some of the monsters have been redrawn as well to feel like they fit in better with the game. The same crappy designs apply, but the coloring and style doesn't make them feel out of place anymore, so it's at least an improvement. Medusa being one of the most obvious examples. Fans of the mainline SMT games will also be pleased to see that SMT4: Final/Apocalypse serves as the final chapter of the plot that spans between SMT1, 2 and 4.
Those are the most important things that were fixed off the top of my head.