Mmm. May as well make my own VPDS comments.
I'm on C3 right now(Just finished the pitifully annoying Rosea A route battle.).
My reactions seem to between the top and bottom on this.
On the one hand, Sin is a conceptually very VP system that rewards positioning and strategizing into a single fast kill. One could argue that this makes maps too long, certainly...but there's around 25? maps in the game and the game is, by and large, designed around the concept that an SRPG battle is basically a small VP dungeon. Thought of that way, it's pretty reasonably done, although, as a matter of preference, some people just aren't going to like a slower SRPG system. I admit, my last SRPG was one who good endings you for finishing fast(SRW@3), so obviously the slower pace was jarring. But, within it, there's plenty of things to *do* with the slower pace, at least later(Various buff items for harder maps, Guard/Might/Spell Reinforce) and Dash helps with space closure problems(Admittedly the AP cost is there. But...+3 Move basically just makes it Accel except in a game where it matters more, for more of a cost. It comes out ahead.).
However, I dislike Sin's trappings. There were parts of it that made things unecessarily long. You have to move people around annoyingly to chip because the game neither allows you to stop a combo in the middle(in a game whose system allows for easy chipping with one start button press!), nor does it allow you to attack with only X amount of people when they're in range. This wastes time and makes it easier to fuck up. Slow pace is one thing, wasting my time is quite another.
The thing is, outside of Sin, I have no real complaints with the gameplay, by and large. That Rosea map is fucking stupid. The early maps suffer from a smaller party, but I can only complain a little there about the game waiting two maps (real) maps to give you a full party. But, ignoring that? Generally there's plenty of maps that feel like they're not rolling over and dying, that they're giving me great challenge, despite me doing my level best to break the game, abuse slower tactics, and generally work optimally for raw smashing strategy rather than for a speed/survivability/damage blend. I don't say people have to like this system, but it's just another preferential thing, not really a flaw.
Rewarding speed's cool and all, but in a short game built around a lot of ideas that would be hard to implement with speed(Sin, team combo from range in general. FM4 implemented the latter. Guess what? It's not fast no matter how hard you try.). There's just some ideas that you can't really pair up with speed. I mean, okay, it'd be nice if the game had some kind of secondary reward system for speed over Sin but that's just a feature implementation lack. It'd be nice if the game had a real fast reset too(I can excuse the lack of a real mid-battle save. No soft reset though? Man that's just not nice when I'm trying for 200% Sin in every fight.).
AP as a system...AP by and large is not a big deal, as the skills it uses tend to be more ephemeral strategy elements than they are actual boosts to a fight. Sure, you can abuse WAY OF REGENERATION or something and take fifteen years to heal or you can just cast Heal. Or throw items. And neither should really consume enough AP to matter. And if the regen didn't exist, these would be balanced horribly badly and would need to be completely overhauled. Really, if you think of it like VP1 items and VP2 spells combined(That is, free items and small nuisance value cost for spells that doesn't counter balance them.), it feels more reasonable.
Pluming as an idea is really a much more interesting form of Transfer. I don't see how you can *possibly* complain about it over VP1's worthless version and VP2's "lol aftergame twinking lol" crap. Certainly, it could be faster as an instant win button, but it still is one, and again, see the "Small dungeon more than SRPG map" feel I feel the game gives off for why I don't really think that's too unreasonable. There's only so much you can do with the skills(Which tend to not be layerable due to massive AP costs), and you game over if you overly abuse it for battle skip, in such a way that you can't get stuck from what I gather(Until the final chapter...which has too many fights to Plume through all of them.). It's one of the most unmitigatedly positive ideas about the game...gameplaywise. As a plot thing, I don't know how I feel about it being linked to which path you're currently on.
Aesthetically, the game *is* ugly, relative to VP. It's saddening. It also ripped off VP1 for all it's music. Which is a better idea.
I have no real idea about the story yet because yeah random political intrigues that feel like filler until the game hits a last chapter where you actually follow the damn plot. Granted, knowing that C5 is like a third of the game and has logical plot-related final battles may be giving me a false impression. We'll see! This does not give me the best of impressions of the plot conceptually, admittedly, but VP1 was no better. Replace politics with demons, and add somewhat better/less character work. Demons are cooler, but I'm not going to say it's a big deal here.