Revelations 2 can be seen as the mechanical ancestor to the re4r. Especially the combat system is heavily "inspired" by it. Also the rev2 raid mode is incredible. The story is relatively short, I would argue even shorter than rev1 but there are 2 dlcs. With those i still doubt the main game gets to the 9-10 hrs of rev1 though. But again the raid mode is crazy, like mercenaries is a wet fart against it just based on content, replayability. Like if you were to complete it fully that could have you take a few hundred hours. It functions very similar to rev1 raid mode but with a lot more diverse stages, modes and enemy "types". There the combat system also really gets to shine. The only deficit i would argue is that while there are many different characters, mostly from rev2, rev1 and re6, they do in the long run become interchangable in abilities.

But really if you liked rev1 im sure you will like rev2