That was an IGA thing. He claims that Female warriors are not historically accurate without actually having done the research himself. Take Joan of Arch as a good example. She was fighting for France in the early 1400's (1412 to 1431). This is before Sonia's time so I don't see why Sonia Belmont is unrealistic. Joan of Arch was a Knight wearing full-plate mail, brandishing a heavy sword and shield, and was ass-kicking the shit out of the English forces. In fact she was the leader of the french armies due to her skills as a tactician and was a spokeswoman of God. We also have the women of ancient Sparta, the Amazon tribeswomen of Greece and the Celtic/Germanic/Nordic warrior women of the northern European lands.
OK. Not for nothing, but IGA wasn't really wrong. Historically women, in general were not warriors. Look, I dig the whole equality thing, but lets not pretend that there were droves of Joans and Mulans running around. These figures were exceptions, they were not the rule by any stretch of the imagination. Also, the Amazons are mythological, LIKELY based on real warrior women within certain cultures, but still a minority.
It's an old trend in fantasy fiction in general. More often than not when there are delineations based on sex women are the spellcasters because they're generally smarter. There are of course always exceptions.
That all said, Castlevania could use another Sonia.
And It does bug me that all the women protagonists in CV are nothing more then magic users and have secondary roles. The only exception is Shanoa. While she is THE main protagonist in OoE she is still a magic user. She is unfortunately not a Belmont nor does she wield the Vampirekiller. IGA had a chance to shine here but he fell short of it (and I'm assuming it was due to personal feelings about his dislike of women warriors).
"nothing more than magic users"? I take exception to this statement. Give credit where it's due. The spell-casting women of Castlevania generally have the most powerful attacks in their respective games... and ALWAYS without the advantage of being a Belmont.
I don't see that IGA could be said to dislike women warriors. If anything, Shanoa is an example of this. Yes, she's a spellcaster. However, she is also a very capable warrior. She doesn't summon weapons to fight for her. She summons them to use in melee combat. On top of that she's also a powerful mage and is even capable of using some of Dracula's own spells. And she defeats him WITHOUT the help of the holy Vampire Killer. I don't see someone who dislikes women warriors putting as strong a heroine as that in one of his games. I don't see how he fell short in any way.