Onimusha is one of my favorite franchises since I was a kid (imagine my shock at Way of the Sword announcement lol, deep down I always believed it would come back), there's nothing quite like the pacing of action and exploration in this game (maybe Ninja Gaiden Black,) and when it comes to my favorites, I have a hard time picking between 3 and Dawn of Dreams, but in the end I think I had the best time with Dawn of Dreams, I completed it so many times, including the unlockables doin Dark Realm for all characters, even if I lost the save I would simply shrug and do it all over again because I loved it so much.
Even though I don't have a ps2 anymore I still kept the game.
As it turns out emulating it isn't Ideal because of some strange enemy behaviours that makes it not a precise experience of what this game truly offers, so I believe voting for a port would be the best.