20 hours in and I'm *still* using the Dragon Sword from the Mines with Strohl, haven't found anything that outclasses it yet. Truly one of the best pieces of gear so far and you get it so early on. Having said that it's reached a ceiling for DMG potential based on how far along I am, should be something better soon.
It's interesting that I still haven't discovered any synthesis attacks with Mage, currently leveling towards Magic Knight, think that might have something. I also wonder about having 4x of the same class and whether that opens up some powerful attack, we already know there are passive benefits. Maybe there are specific combinations too like 2 Mages x 2 Warriors that access special synthesis, need to experiment more.
This might be obvious but maybe not so it's worth mentioning. You don't need to actually switch to a new archetype/level it to gain access to it's base abilities, just unlock it. In other words, if I want my Knight Hulkenberg to have a healing spell available just unlock Seeker, don't switch to it, you can now add Dei (or Cyc if you need access to some elemental DMG) to your inheritance slot