I love the OVA. I have the manga, but only enjoy it up to the defeat of Shishio. The manga series really jumped the shark after that. The only part I like that comes after Shishio is Kenshin telling his Hitokiri Battosai story, which is what the OVA is based on. The manga is a lot more detailed as to history than the show, I think.
Unfortunately, I don't have too much an interest in samurai and Japanese history. No more than I do in any other country. I'm interested in a few specific things about Japan and even plan to visit one day, though.
You ask a lot of questions; it's very Fe-like. You're an INFJ?