Well I can somewhat explain the plot of CV2 using some wonderful existing theories from other series.
**ahem**
Perhaps, when you collect the body parts to do a Summon, you're not just doing a regular summon but rather, like Dracula's regular Resurrection methods, you're gathering all of the evil of the surrounding area, harnessing it, and channeling it... INTO the flux capacit-errrr I mean, into the PEDESTAL. Thus, by bringing all of the evil together into Dracula's Remains, you're essentially cleansing the countryside.
It is similar to how every 100 years, upon a natural resurrection, the evil of the land as it grows summond Dracula. By gathering all of the evil in the ritual, you're taking all of his 'curse' and bringing it to one concentrated spot. The resurrection is a result of this ritual and the gathered parts.
I think it has been established that a prematurely resurrected Dracula just does not have the power that a full-power properly resurrected Dracula possesses. It is possible that the Dracula that Simon defeats in "Castlevania" is a full-power Dracula, with enough magic power to put a hex on the entire area around his castle, while the Dracula summoned in "Simon's Quest" is just too weak to do such a thing.