To Love Ru would be better off as a secondary world then a base world. It's simplistic enough that you can slot it in with a decent amount of other series but at the same time it's too simple.
Kyoto hitmen reborn, beyblade, air gear, kid muscle, tenchi muyo, code lyoko, maybe digimon, Kenichi and maybe persona. That's all I got for ideas
I just remembered there was a mini arc in the manga where Rito and Lala entered a digital world to meet Nana and Momo. Digimon could oddly fit in there.
Well, how powerful do you want? Do you want to maintain the general ecchi slice of life atmosphere? In between insane battles, that is?
I recently read one fic with Baki and Kengan Asura in it and i thought it fit really well. Also you could add multiple fics that are space themed like Steven Universe or Gintama aliens from the previous commits. Then add some fics that are set on Earth mainly, just to spice it up.
Maybe because its too complicated for them to write it up since lets face it, most fanfic authors in my opinion tends to stick to one general place with them maybe writing up the MC's going to another location temporary for a short time before going back to their main area sort of how Persona is like. Psyren on the other hand, literally has the MC's going back and forth, not to mention you have to write up the changes of the different timelines is itself, a major headache than having to just write a world with one main setting and possibly, a secondary supernatural world. Also, my opinion of Jordino's fics is that generally speaking, it has quite a bit of smut since pretty much most of his fics has him laying down with many of the females and from what little I remember of Psyren itself, its not one that has ecchi or harem in it so there's not a lot of love interests for Jordino to write up about.
