"I mean RE4 on PS2 had fewer zombies"
No. It had the same. It really did. I've played the GC, PS2, and Wii versions plenty of times. The PS2 version has lower color depth, lower polygon count, reduced lighting and sound, longer loading, and FMVs instead of in-game scenes because of that lower loading. It did not reduce the number of enemies. The trees an leaves in the first third were fewer, but not the enemies.
A flashy-first game is awesome when it comes out. A great-first game is awesome forever.
Plus, just for the hell of it: Kelly Brook at the 2008 BAFTAs