I find myself agreeing with all of this, although the alliance and commander bother me a lot more than Lana.
It's sad that the base game's original class stories were all about this building conflict between two iconic Star Wars factions, a cold war that erupts into an actual war to set up the endgame.
Yet at the first sign of trouble Bioware abandoned this. The very first expansion, presumably already in development while the game was still performing well in early 2012, had us fighting... the Hutt Cartel.
Then SoR took it one step further by even having Republic and Empire collaborate against another common foe, before we got KotFE. The weird thing about KotFE and KotET is that they have relatively high production value and many hours of single-player content, but Bioware still could not or did not want to figure out a way to make it be about what their game ostensibly set out to be about from the beginning.
Lana I can live with, but I actively dislike the "commander", the alliance, Valkorion, Odessen and Zakuul, because even though it is not terrible content in and of itself by any means (actually Valkorion/Tenebrae as a concept, being an immortal galaxy-consuming force ghost with multiple personalities is pretty terrible), but because it deviates so jarringly from the direction this game set out in.