Funny you should ask.
I was actually thinking of a sort of Hub rpg for the past few days. (Mainly the party, but y'know.) I'm not 100% sure how RPG maker works, but if you can swap party members, you could have a pretty cool roster. Imagine starting out with just Hypno-Tan, but the starting area is a sort of actual Hypno-Hub, where you can find Erika, Crystal, Naomi and Toon Liz. You've then got a full party, with one interchangeable slot. After that, you'll be able to find new members on your quest of unspecified importance. You might run into Zyii and Ara along the way, bump into Pitviper, and whoever else.
One of the cool things I thought of was at the start, someone (not necessarily me, but totally me), is completely zoned out in bed, and completely unresponsive, then near the end-game, there's a boss battle with Awake-san in her Clock-mech that I keep going on about. After the fight, Awake-san begrudgingly joins the party to fight a common enemy, then you can call back to the hub, and Awake-san wakes that guy up, and they also join the party.
I think it has a lot of potential, considering how many oc's we have, and each being able to fill a class slot.