RE4 looked like a PS360 game on the Gamecube, that's really all you need to say for this argument.
While the original was a huge innovation, it was easily eclipsed graphically by RE2 and many other later PS1 titles. The REmake was very good, but it was like, the 3rd or 4th "Director's Super Special Edition" of RE1 and the game was too stale to be really impressive at that point. RE0 looked nice, but was more of the same as "n" other RE games and shoehorned into the storyline. RE5 doesn't stand out from the crowd of HD titles, let alone loom over them embarrassingly so like RE4, it also dragged Umbrella and Wesker kicking and screaming back into the narrative (I'm supposed to remember some random characters that I mostly just read about in files from RE1-3, more than 10 years ago on the PS1?)
RE4 was such an incredible breath of fresh air, innovation, stunning graphics, and an (almost) clean break from the tortured and bloated Umbrella storyline, that it impressed on every level and was easily one of the best games of the last gen (and my personal favorite).