I've played Vampire: The Masquerade – Bloodlines 2's DLC clans, Lasombra and Toreador, and they absolutely should have been in the base game

They are, although in the time since Bloodlines 1, the metanarrative has shifted a fair bit. The Sabbat are no longer a significant force, and instead the main factions are Camarilla and Anarchs. And there's a lot more individual choice (or at least...the choice of one's Sire) involved, so toreador anarchs would not be nearly as unusual as a toreador Sabbat member would have been in 2000.

Seattle is ruled by the Camarilla still, though.