Wasnt really far up in the pipeline(currently DMeta then SQ was my plan right now) but I could see myself switching him/SQ around if desired, sure. Of course this requires me to not be lazy about plusses so I wouldnt hold your breath on that. I can try though!
Mad respect for him for clearing half of the Mythicals for me, after all.
Don't push yourself if you weren't planning on doing that anyway, but if you do hypermax him I'd be happy to use him.
Out of curiousity, what is it that Hermes provides for you that Ryune doesn't do better? Double Attack Stance proving more helpful than a BDH board with Haste 1 sounds crazy in type, but since I don't have the practice of using your Gabe enough to know how the two work in practice(and lack either Gabriel or Ryune to compare) I can't say on my own.
I'm not a fan of boarchange actives that create three types, really. Making a ton of blue and hearts is nice in theory, but it's too likely that I'll get too few blue orbs to be able to do rows. I prefer a reliable, predictable active most of the time than something that can fuck me with RNG. There are exceptions, like when I need to wipe the board clear of poison in Devil Rush or something, but they're rare. A double orbchange consistently gives me enough orbs to do two rows, a boardchange consistently does not. And haste rarely matters for this team because I tend to use my actives in a certain sequence when I know it's time to kill something, so usually I'm either using her when my other skills are off cooldown anyway or I'm ending the dungeon with her unused because she's not part of my big combo.
Two skillboost is also extremely valuable to me since lack of skillboosts is probably my team's single biggest flaw. Just one extra skillboost can make a huge difference on dungeons with countdown first floors, especially since Hermes' active has a significantly shorter cooldown than Ryune's. Three rows and one prong is much better for me than two rows and two prongs, although with the significant drawback of only x2 attack instead of x3. I don't know how the exact math on that works out, I'm guessing damage is in Ryune's favor by quite a bit, but outside of Gabriel/Gabriel setups my damage is usually enough to do anything I need to do once it comes around to burst time.
It's notable that Ryune doesn't have an ultimate yet and Hermes does, so once she gets her ultimate form I'm sure she'll be hands-down better, but that will probably be a very long time from now. In the meantime Hermes is slightly fast and much more consistent in exchange for being weaker and arguably lower-utility, but I'll totally take that most of the time.