This is getting to the point where I'm starting to doubt he has a hybrid form ( I mean I 99% believe he does but this is getting really silly)
Loki's Hybrid knocks him out of commission for a few minutes like Luffy's Gear 5 does, IMO. But, Loki is:
A: Smarter than Luffy and
B: Stronger than Luffy
So Loki doesn't need to go into his Hybrid Zoan that often, and only saves it for when he REALLY needs it, since Loki being out of commission for 5 minutes or so like Gear 5 would be VERY BAD for someone as big of a target as he is.
Also, considering the gap between Luffy and Loki at this point, with wounded Loki wildly outperforming healthy Luffy without using his Hybrid, and then considering the gap between Loki's Giant Warriors and Luffy's strongest Nakama, and it really makes sense Loki isn't using his Hybrid that much in general, if it takes him out for awhile. The Giants around him just can't keep up without him. It's like Marines in Halo when they do or don't have Master Chief. The moment Chief leaves the room, the Marines are all getting killed by mutherfucking Invisible Sword Elites.
I think we'll only see Loki's Hybrid when he's actually on 5% HP, and knows he won't be able to continue, no matter what. I think Loki's Hybrid drains his Haki/Stamina massively, it might last even shorter than Gear 5, especially depending on the size. Like... is Hybrid Loki closer to Zoan Loki or normal Loki in size? I imagine he can alter the size, but to what extent?
I wonder if we'll see Sogeking Usopp or Hyrbid Loki first?