He is called literally the strongest being in Earth. In raw power he is stronger than anything.
I don't remember where, but it was stated that the only things that really damages Dracula are powerful magic and the Vampire Killer, and almost all the vampire hunters in the series (except Shanoa from Order of Ecclessia and maybe Charlotte from Portrait of Ruin) are related to some degree to the Belmonts. Usually the subweapons are imbued with the energy of the user, and when the characters begun to use other weapons besides the vampire killer, either the weapon is magical and really powerful (the Alucard Spear) or the guy is really powerful (Alucard, Soma, Jonathan Morris)Consider me fooled.
Also, regular gear being worthless against Dracula has no precedence that I can recall. The Vampire Killer is very effective, but that doesn't mean mundane weapons are worthless. I certainly don't recall any story details that say as much, and considering that every protagonist to stuffed full of subweapons like axes, knives, and a few holy talismans, I'm not convinced Dracula is 'in story' immune to mundane weapons. He certainly isn't in gameplay.
Maria Renard is as powerful as some of the most powerful Belmonts. It's like saying that Shanoa is dangerous towards Dracula. In fact, Maria is stronger than Shanoa in sheer power. Shanoa is just more versatil.*headdesk*
My point is that while they have credible ways to hurt him, Dracula is not so overwhelmingly powerful that they are as ants before him. He might toy with them at first, but he eventually pulls out all the stops and he still loses.
As for non Belmonts, I wasn't thinking people related to Dracula. I was thinking people like Maria from Rondo of Blood and Symphony of the Night. For the record, Maria can beat Dracula in Rondo of Blood and she's still a child. I can't even call her a joke character, because when she returns in Symphony of the Night she's still a threat to Alucard in battle.
I don't remember why the Belmonts dissapeared after Ritcher till Julius Belmont finally kicked Dracula's ass, but the guy you mentioned is Jonathan Morris, a distant family of the Belmonts, almost as powerful as them and trained since he was a child to fight vampires. And he has Charlotte Aulin's help, and she is one of the strongest magicians ever. The guy with the Alucard Spear is possibly related to Alucard and the spear is a strong magical weapon, almost at the level or at the level of the Vampire Killer.Moreover, the Vampire Killer left the possession of the Belmont's after Richter, and other non Belmonts used it. Even though it gobbled up their life to use it, they still beat Dracula. I'd have to do research, but I'm nearly certain that non Belmonts have successfully killed Dracula without the Vampire Killer. One guy had Alucard's Spear, I think. They might have also had the Vampire Killer, but in one game it starts out piss weak and the main character has to beat the memory of Richter to unlock its full strength. They can still beat Dracula without its full strength, but I can't guarantee that the True End is acquired.
So yeah. Lots of non-Belmonts that have kicked Dracula's ass. Dracula may be incredibly difficult, if not impossible, to permanently kill, but he is not someone I'd consider equal to Crimson Moon. Not without more evidence.
To be fair, everyone who bested Dracula in the Castlevania's saga would qualify as a Legendary Soul in the Nasuverse. At least, powerwise.