Not sure if you've played Bahamut Lagoon (jp-only snes game that eventually got fantranslated) but this game seems to do a similar thing to it where your entire party is broken up into sub-parties that move around the grid like in FFT and then when you encounter an enemy group it transitions to a jrpg style combat system where it's more zoomed in and each char has a lot more detail than you find in Srpg animations. And if you have the typical Srpg limit of around 10-15 chars, but those are 10-15 4-char groups instead, I can see fitting all those chars in a single party. Of course that wouldn't be for most of the game cause I imagine you would have to jump through hoops to get every char, but, say, 30~ chars or so is feasible to have simultaneously.60 members isn’t a party, it’s an expeditionary battalion
And hey it's not as bad as Eiyuuden (which also got a release date finally, Aprli 23!), that one will have like 112 chars lol. I kinda lost track of how many addons we got, but I know it beat suikoden's 109 for sure.