And that pirate would be...who, exactly? I know you're not talking about Grant, because Grant wasn't a pirate. Ever. In any continuity. And to refer to Grant as such would only reveal your ignorance of Castlevania and its history.
Doesn't the manual in CVIII specifically say Grant Danasty is a pirate?
Personally, I would just add more details to each game's story. I know there are some who don't care much for story, but I've found that a good story adds to the enjoyment of the game. I've always thought CV has potential to make a good story.
Specifically what I would do is I'd link the rebirth process seen in LoD to the reincarnation seen in AoS. "Dracula" can take on a new body when his current one wears out. Also perhaps develop the idea that Dracula is a force of nature rather than a specific person (Mathias, Malus, Soma). In other words a person can become Dracula, likely by fusing the Crimson (?) Stone to one's soul. The soul then takes possesion of the body. Something along those lines.
I agree with what someone said before that there should be a level of drama when facing certain foes like Death. I mean it is Death. That said I would make it clear what Death and Drac's connection is. What purpose does Death serve? Is there a Devil in the CV universe? Do they all serve him or is Drac the devil? Overall I think the motivation of Dracula and Death should be made a little clearer. They are after all the only recurring characters who appear in every game and yet we know very little about them.
The last thing that comes to mind is that CV really needs more vampires. Dracula is Lord of the Vampires and yet we see very few around. Belmont's hunt vampires yet aside from CV64, we don't really see them killing vampires aside from Dracula. Dracula's role as leader of the undead really should be expanded upon. I also think vampires as an enemy in the game would make a good addition.