This title was, at first, promising when I'd been giving it a try via Game Pass. However, given the state of the game at Launch, along with content that should have been at launch being served piece-meal as if the game is a live-service.

Wait for a fire-sale, consider looking for the earlier titles by the Coast, or just jump on MW5 Mercs' "affordable" price of fire-sale. Just... if you want a story-mode, the MechWarrior 4 games are on the high seas; if you want PvP, play Living Legends instead of MWO.

Edit: Trials of War has gone free. However, this review should stay up. To be blunt, many of the features that made expansions wonderful in the old days make current DLC trends awful.
Clans, as a stand-alone package, needs to stand on its own, and the Story Mode only goes so far as it's the modern equivalent of 90's FMV cutscenes with pre-Pixar realistic CGI instead of live-action. Even though it does tackle the narrative of the most controversial of the SLDF-in-Exile's Clan Heirs, Clan Smoke Jaguar; it files the fangs off of the faction that should be the most vicious of the eugenics-born Invaders that were once the survivors of the ruined Star League. Much of what I'm saying makes no sense to newer fans who haven't done their homework, and that is the core issue of this game's plot: much of the impact comes from knowing details and narrative elements that the story can't just give the audience (which rival franchises can get away with by having their stories set in the periphery of major events instead of within them).