I would prefer an advanced gameplay style to the first Parasite Eve, somehow take advantage of the ATB and real time system they had and evolve it.
I will also accept the 3rd Birthday gameplay style and being tweaked. Removing the overdive system of jumping into comrades would be a big plus for me. Also make use the the PE system again, not gonna lie I haven't played The 3rd Birthday in awhile, I plan to pick the game u again for another playthrough. I don' recall it having a big emphasis on PE during battle as the first and second game. So I would enjoy seeing that element into the game if it was more of third person shooter again.
The game with the less favorable battle system and presentation in general is PEII, still a great game but not as enjoyable as the original and I often found the 3rd Birthday to be more enjoyable than PEII in terms of gameplay. The story was a mess tbh...