Nostalgia value is totally subjective. I wonder how a game that's 10 years old could be considered to have low Nostalgia value, though, unless it was bought used recently. Well, actually, I did play Castlevania after Castlevania 3, so 3 has more nostalgic value to me. In fact, probably the thing I like most about Castlevania is that it reminds me of Castlevania 3. And I also don't think Castlevania 4 has the best non-RPG soundtrack - IMO, SotN's is many times better, and, IMHO, the best soundtrack ever, RPG or not.
I LOOOOOOVE Flying Omelette!