In Simon's Quest, only two bosses outside Dracula appear, and they are both easy by Castlevania standards. While this is probably just coincidence, considering that Dracula himself is also easy, take note that the two bosses are Death and Carmilla, two faithful servants of the count. Why would they want to stop you when you are trying to resurrect their master? Both are probably going easy on you.
Fridge Horror: And what's worse about this, we've actually seen it happen already, although not within the confines of Castlevania.
Dracula being relatively weak in this makes sense in that this method of resurrection didn't revive him at full power. This is potentially offset by Simon possibly either too weak by rushing or took so long to build up his strength that the curse kills him anyways.