Agh, missed a lot of responses, so I'm just gonna @ people.
@SVS Eye of the Mind doesn't have to make you include vastly more detail, the important part of it is that it's a spur of the moment combat thing, where Homura (if she had the Rune) could dodge vastly faster/stronger enemy's attacks like Archer does against Lancer in F/SN, and it would also grant her vastly increased capability offensively against her opponents that excels at taking advantage of weaknesses; one example being her shooting her bow at just the right angle and predicting where her opponent will be on the fly to accurately shoot them in the heel between a nick in their armor.
@NMS I linked you since you never really acknowledged my argument against going down that path, namely that drain would probably be useless against Homura's primary enemies, Witches and familiars (and especially Walpurgis); Witches don't have stamina nor do they have a cap on magical energy (presumably). If we were to go down another Isa path I'd highly recommend the time slowing one, as that debuff would work against just about everything that's not Kirika.
I'm casting my vote for learning
Inguz as that's what SVS recommended
. Here's what I'd previously written about it:
Inguz: Storage of mana and/or life energy in the rune/object it's on, can eject the mana and/or life energy in the rune or from an object it's placed on, increase passive regeneration of od (life energy), hypnosis magic
Homura might be able to "eject" grief from Grief Seeds, might be able to passively reduce grief in Soul Gems over time, can store all kinds of magical energy for a variety of uses; she could carve
Inguz on accessories for her friends/allies to grant them the passive grief reduction/for them to have a store of magical energy on hand; she could give a passive od regen to Hitomi as she'd benefit from it as well. The whole ejection of grief thing would more than likely work, btw, since the Incubator is able to take grief out of Grief Seeds in the first place to harvest the grief for energy.
EDIT: Actually nvm on the whole having Homura learn
Inguz thing; if
Inguz could do that why not just have Lancer do it for the team?