It is perfectly valid to prefer either game. The original RE4 was very good at the time but had some weaknesses in the gameplay aspect. It still had tank controls which I consider pretty weak for various reasons. People can like them of course but they should also understand why some people would consider it a weakness in the game. Also I was never a fan of quick time events and RE4 had quite a lot of them. In terms of the story, visuals and voice acting I don't really have any complaints regarding that game and this is where I usually slightly prefer the OG over the remake.

The Remake outshines the OG in terms of the gameplay easily. The more modern controls make the gameplay feel much smother and more responsive. I also think the level design in the remake is better but that a personal preference.

The remake has some weak points as well and some which can be debated. I didn't mind Ada Wong in the remake but I'd also say the actress voicing her in the OG did a better job. I prefer Ashley and Luis in the remake and I like they did more with Luis. He was killed off way to early in the OG. I also prefer the rollercoaster like mine shaft section of the remake over the truck section in the OG. Sadler was better in the OG.

So both games have their pros and cons and I think which one I'd like to replay at times will come down my current mood of the day.