I tried it but I couldn't get over the fact that there is no dedicated parry/block button. Also the game looks horribly dated with muddy textures and environments.

It doesn't have the soul of a Metal Gear game. Its quite literally Bayonetta with a Metal Gear reskin. Metal Gears gameplay is mostly about player freedom. You have to get from point A to B and how you do it is up to you. Rising takes all of that away, just hack and slash to kill everybody. Its still fun, but definitely not a Metal Gear players cup of tea.

I had the same realization about 40K Space Marine (the old one). When it originally cane out I loved it, but I replayed it a few months ago and realized that its kind of bad. Its just corridor, arena, corridor, arena, corridor,... There's not really anything to it, not even the story. Why is it so highly praised? Because back when we first played it we thought it was cool and nostalgia is a powerful thing.

I only played Rising recently precisely because back when it came out it deviated so much from the first Trailers. I wanted Metal Gear Solid 4 but with Raiden, but what we got was Metal Gear Devil May Cry.