I personally think it fits really well. It sounds hopeless and that is how many players feel fighting Flamelurker the first time. There is no gimmick, no intrigue, no climax. It's just constant tension as you carefully hit and run while hoping Flamelurker doesn't annihilate you with an explosion.
The new theme doesn't get that hopelessness across. And that's the biggest problem with it.
Almost every From boss makes one feel hopeless. It's not unique to flamelurker.