Firkraag’s dungeon is indeed particularly good dungeon design. It is only unfortunate that, like most BG2 dungeons, it is quite shallow, with only one level. Compared to stuff like the Nashkel & Cloakwood Mines and Durkag’s Tower in BG1, Watcher’s Keep in ToB, and Dragon’s Eye/Severed Hand/Dorn’s Deep in IWD, the BG2 stronghold dungeons are all oddly flat. I’ve never known why Bioware did that.

This sounds like it is working very well, on both the player and DM side. I can only imagine that the IWD/IWD2 campaigns would work even better… those are setup more like straight conversions of tabletop modules.