The vanilla Star Wars maps can be played using the Mass Effect factions and gameplay, it's just a simple case of selecting 'Mass Effect' when picking between 'Clone Wars' and 'Galactic Civil War.' The reverse, however is not possible (Putting Rebels and Imperials on Virmire). Mass Effect Unification is best viewed as an expansion pack for vanilla SWB2 Classic as you can easily queue up a series of Mass Effect and Star Wars maps and the game will flawlessly alternate between them (Quick disclaimer: No, you can't pit the Empire against the Geth or Collectors, sorry). Perhaps one of the most in-depth I've found however, is Mass Effect - Unification for Star Wars Battlefront 2 (Classic). While I feel it's unlikely that we're to see another entry to the franchise given the comparatively poor response to Mass Effect Andromeda, the still lingering controversy over Mass Effect 3's ending, and the dwindling state of publisher EA, there are a couple of mods for various pre-existing games that can add Mass Effect related content to these games. It's been seven years now since the Mass Effect trilogy came to an end (and two years since Mass Effect: Andromeda) but the franchise remains one of the most popular sci-fi RPGs in the genre. The image above was taken via Star Wars: Battlefront 2 (Classic) with the Mass Effect: Unification Mod installed.

Star wars battlefront 2 mass effect mod