Mini-rant/infodump incoming: I imported this on release and was slightly disappointed at the not-EOness of the game(stopped around stratum 4). Spoilers ahead, etc.
Bad:
-No skill trees. I can understand why, but still. It's skills by level, Persona style. Higher level skills (agi->agilao) replace the previous. Characters only learn a maximum of 4 naturally learned skills.
-With no skill trees, team synergy is less of a thing. There aren't really any interesting passives or "builds" in general, so just throw together a team of characters and go ham. Skill cards allow characters to fill almost any role, though their stats may not be as good as the "real deal". Might be a plus to some.
-Some strange balance choices as far as I can see? ex. I chose P3 MC and noticed that he seems inferior to P4 MC in almost every way. He has TWO weaknesses, no strengths, meh defense, excels in magic, but uses a close range weapon so you basically have to put him in the front row if you want his melee persona attacks to do any damage. Meanwhile, P4MC has one null element, one str element, and one weakness, and has more well rounded stats.
Good:
-P3/P4 fanservice delivers. If you like P3/P4's characters then you will like this game.
-NO MORE ONE MORE SYSTEM THANK YOU BASED EO TEAM. New system is hit weakpoint -> get boost status. Boost status is removed if you get hit before your turn. If you make it to the next turn in boost, your next action will always go first and cost 0 HP/SP.
Different:
-All characters can equip one sub persona along with their main, which is locked. The sub persona adds to their HP/SP and move pool, and refreshes every fight. Ideally you only want to use resources within the sub persona pool unless it's a hard fight.
-Skill cards are a thing. I didn't play P4G for very long, but the way it works in this game is you sacrifice a persona and money to gain a skill card(skill depends on the persona). The skill card can be used for adding a permanent skill to a party member's main persona, which each have 4 skill slots along with their 4 natural skill slots.
-Leader skills(or as I like to call them, navigator skills) are skills personas have that can only be used by the navigator character. They're basically EO3 bursts that use a universal bar, and can be activated at the start of a turn. Ideally you'll want the navigator's sub persona to only have these skills, since they don't actually participate in combat.
-Massive SP costs. The -dyne spells cost something like 48SP, and my SP pools were around the 120-160 range in stratum 4.
tl;dr combat-wise, I feel like it's a gimped EO, but still better than P3/P4.
STORY JUNK
-If you like social links, prepare to be disappointed, because social links don't exist in this game. There are scenes involving a bunch of characters, etc. but no Persona-esque stuff that actually affects combat/personas.
-As far as I've heard, the "routes" are essentially the same. The main difference I've seen is what characters you have access to in stratum 1, otherwise the choice is basically just "who do you want to be mute".
Bad:
-With no skill trees, team synergy is less of a thing. There aren't really any interesting passives or "builds" in general, so just throw together a team of characters and go ham. Skill cards allow characters to fill almost any role, though their stats may not be as good as the "real deal". Might be a plus to some.
it'd be real shitty if a fanservice game ended up forcing you into using specific characters because some were better than others or had buildpaths closer to what you want to do gameplay wise. the draw of the game is to be able to be able to use whichever waifus you want, although i guess they could just have had everyone with the same skill trees and just make the tree all-encompassing, but that might have been too complicated for a crossover-ish game aimed more at persona fans than EO fans
it'd be real shitty if a fanservice game ended up forcing you into using specific characters because some were better than others or had buildpaths closer to what you want to do gameplay wise. the draw of the game is to be able to be able to use whichever waifus you want, although i guess they could just have had everyone with the same skill trees and just make the tree all-encompassing, but that might have been too complicated for a crossover-ish game aimed more at persona fans than EO fans
There are like a zillion difficulties, so it's very unlikely that you'll be forced into using a certain team unless you play the hardest one. For example, on Normal my team was P3MC/Akihiko/OCsdonotsteal Koro/Aigis with Fuuka assist. I've never needed to sub in a dedicated healer due to subpersona move pools/Fuuka healing burst ability. OCs do not steal is also the jack of all trades character, they have attacks with most of the basic elements, attack/defense line buffs, and a line heal. They can't use subpersonas or skill cards though.