Thank you for your reply,
About the High-elf summons, I think that their power would be okay if common enemies perceived them more of a threat than they currently do, and tried to kill them quick. Most of them always go for my mage that can kite them around.
I do not know how much agency you have on AI behavior, but "bosses" do not seem to have that issue. When I fought the Griffin for example, the first thing it tried to do was to kill both my summons, depriving my mage of the essential buffs that they provide. Her casting suddenly felt like molasses, with less damage output, and whenever she got hit the lack of hp-regen was very noticeable.
However, I agree with you that it's a (subtle) matter of balance that it is NOT easy to achieve, because the other extreme would be equally undesirable (enemies totally ignoring my mage, with summons "tanking" them).
About the Sublime Guardian, whenever I summon her, she properly looks for and engages enemies, but see does not hurt them at all for what I can see when my Seraphim stands back. I do not know the insides of game enough to tell you if it's because she lacks "attack", or if her weapon lacks "damage", but it happens with any kind of common and low-level enemies that I've pitted her against. I first thought it might be a matter of resistances.
Anyway, as I've said, these are only nitpicks as far as I am concerned. I rather prefer summons to be somewhat over-powered, in which case I can chose to call and use them situationally, than blatantly underwhelming, in which case I can't do anything but perceive them as totally useless and ignore them. Some powers are like that in the vanilla game. The "Sublime Guardian" as she currently comes still has her use as distraction against bosses just running around, pretending to swing her blade around and looking pretty ^.^
Hehe, thank you very much for the welcome