I don't feel the older titles captured more brutality, and I don't think they were as immersive in gameplay or story. Part of what kills the old titles for me is the isometric view, which makes Kratos look more tiny than brutal. In fact the scene you showed also has him platforming up the monster at one point, at which point TR comes to mind. The arcade stats plastered onscreen don't exactly lend any realism either, quite the opposite. Another thing I didn't like was the QTE, which was horribly implemented.
There's also the fact that GoW 4 outsold GoW 1, 2, & 3 combined, so there's very little incentive for them to dump more money into the old titles. Clearly the fanbase has voiced their opinion on what formula they like the most, and it isn't the old stuff. With consoles now capable of high end graphics and 4K, isometric views and the fixed camera angles such games use are quickly becoming outdated. In my opinion, it's about time that happened, because consoles for far too long were always slowing down progress.
Now that the core GoW fanbase has had a taste of our hero fighting in a more real looking, up close 3D world, I think a mere remaster of the old games wouldn't be enough. They'd have to be completely remade from the ground up, with the new style, and that would be like making a whole new game. For this reason, I think they are better off leaving well enough alone, and continue to develop the new games just as they have. I personally can't wait to play Ragnarok, it looks like it's going to be every bit as good as 4.