Legrnds of hermes has quite a ton of ideas here for original research. Or stuff that you can extrapolate easily enough. My (and others') review of the book:
https://forum.atlas-games.com/t/card-board-games-archive-links/116/1
Look at the review of Conciatta, Herisson and Fortunata. All 3 of them did original research. From all of them there are lots of stuff you can branch towards. I suggfest one such case in the Conciatta review, but it is not the only one.
As a side note you can also do MUNDANE poriginal research, like demonstrating that faerie and magic realm lore differentiation is purely theoretical (and that both are a "Legend lore" for example) or that Infernal and Divine Lore are the same since all the power emanates from heaven ultimately, either positive or negative aspects of it.
You could also search for the underlying methods of magic (pretty much what Bonisagus did, but building on the shoulders of giants) and come to realize that all the Hedge Magic theory is just aspects of a grander whole along with Hermetic Magic. You can even end up determining that it is also the same as the Legend Lore above for a grand understanding of the magical forces of the world.
I also favor integrating the 4 elemental arts in a single Elemental Form following on the steps of Conciatta, and maybe going after stuff like a Time and a Space Forms for hermetic magic.
Another smaller option would be to make you able to affect an area around you, something where Hermetic magic fails totally and that is quite a common feature of magic as we know it from stories, modern and old.
Hope that helps 
Cheers,
Xavi