I agree that guns detract from the feel of D&D in a generic campaign, but enhance the feel of Ravenloft. People often think the setting is all about horror & fear, but forget about general "wierdness" that is the core & it islands. Different culture levels laying slap bang next to each other.
One of my favorite characters from our old campaign was a pistoleer, I trawled the 2nd eddition player Option book for every advantage I could muster, he could fire 2 pistols in a single round, would score critical hits most of the time causing massive dammage. I can still remeber he once notched up an impressive 130 points of dammage from a single shot.
Of course he couldn't dammage lycans, incorpreal undead, skeletons only took half dammage and so on. The point of playing him wasn't his combat effectiveness (he was useless otherwise), but the fact that he reinforced what a strange world my companions had stumbled into. More so the fact that this pinnacle of technology that could easily kill any one else in the party at range was completely ineffective against the terrors of the night.