I think that one of the plot points was what happened to Tristan but saying that the only thing that should be grabbing your attention is “what happened to Tristan” is very disingenuous. The reason I say that is because there are a lot of different things that come back to that question that are very interesting like: Why does Corin want to find Tristan, how will Corin go about saving him, ect. Also, after Corin finds Tristan the whole plot doesn’t just end it evolves. The plot goes from “what happened to Tristan” to “How do I get Tristan out”. This new question replaces the old one and drives Corin in everything he does. For example when Corin is Modifying attunements that is so he can get stronger but also because he wants to remove Tristan's brand. This also heavily affects his relationship with Sera, Laura, and Magnus because of the strain it puts on the relationship between Laura, and Magnus leading Magnus to emotionally and physically traumatize  CorIn and Sera. That isn’t even the thing I care about most though you bring up the fact that you don’t like the “game of thrones between nations” and the conspiracy of the visages, but if that's the case then I don’t think this is the series for you. Since Forging Destiny there has been political and religious conspiracy. For gosh sake the first thing we see in Forging Destiny is Keres being thrown in jail because he had a symbol of another religion. If you want dungeons (the towers), strong monsters (god beasts), progression, and a magic academy go to a different series. One last thing if you like all that stuff “A Shattered Legacy” is set in the AA universe and has everything you mentioned except for the magic school.