It's Mechwarrior 2, but for modern sensibilities and people who don't use flight sticks. The campaign is not the central feature, but I do believe it's an important creative focal point for this game. Mechwarrior has a sort of roleplaying element to it; it harbors the ideal of making the player feel like a mechwarrior. How the campaign is laid out, with its upkeep costs and travel times and reputations, builds the player narrative of tearing across the galaxy on a warcrime-and-cBil-fueled mercenary roadtrip. It's a fun adventure!
Two important sour points are that the campaign is way too long and your AI lancemates are dumb as bricks. It detracts a little from the commander fantasy (and actually playing the game) when you need to actively cheese your teammates into pretending to be competent to avoid getting roflstomped by the sheer amounts of armor the game will hit you with at higher difficulties.