I finished this today, a nice solid Teen novel. El has some good growth, but she's still an extremely selfish brat, just less so by the end. Nice solid twist feeding into the sequel bait, which I'll put on my list once some time passes.
I read some reviews which mentioned some problematic sections, when El was discussing dreadlocks that was perceived as racist. It wasn't in my digital copy, so it must have been removed afterwards. I can see trying to write for other cultures being a particularly dicey proposal, and I didn't think El's Indian side came out that much (but she didn't get much support from that side of her family, obviously).
I liked that both Orion and El were Saviors, just with different goals. Orion single-mindedly kills Mals because it's in his nature; his special talents give him an immediate mana boost, but he's not saving people for the love of it. He just doesn't know of anything else to do with himself, and can't not do it.
El's trying to evade her prophecy and lineage, but ends up saving just as many people on her path. She says she's just doing it for survival, but it doesn't really track. She's talked about how for years she's been fantasizing her "coming out", showing everyone her power as a way to move up, and to further her original plans of joining an enclave. Being in the scholomance, she ends up realizing that the enclaves are what's driving their society to ruin, but her acts and politicking ultimately save the lives of the same institutional reputations that she perceives as keeping her in a lower caste.
If this is taking the Hunger Games approach which it's modeled after, I see Book 2 showing how El graduates, continuing to use the system while being beset by horrors the whole time. Book 3 would show her dismantling everything, tearing down the enclaves, the Scholomance, et al, fulfilling the prophecy that her mirror showed her while issuing a new age for sorcerers. If there was a Book 4, it could be a coda showing why tearing down society was Bad, Actually, and she ends up revolting against the new reality that she worked to bring to life.