This game would look so much better with more memory for textures. Thankfully it looks great as is (art FTW).
It just requires smarter texturing, really. There is plenty of ram.
Look closely at Gears of War. They were smart with the textures in the fact that you typically find higher resolution textures very near the player (and 3rd person helps here). If you analyze the environments and areas around you, however, you'll find that they used significantly lower resolution textures to build the environments with the resolution varying depending on where it lies in relation to the player. Not only that, but Gears clearly streams texture data as you move through the world (the pop-in proves this) while I'm convinced that Resistance is taking the PC approach and simply loading each level into ram (for the most part). A different approach to texturing would have helped a whole lot.
It's very much inline with Insomniac's previous works. The R&C games focused on carzy geometry with extremely low resolution textures mixed in (lower than your average PS2 game, I would say). They seem to work on creating detail at a distance rather than detail near you. I don't think texture ram will be a problem for PS3. XBOX360 has a bit more available, but not enough to make a big difference (this isn't like PS2 vs XBOX at all) in the end.
Oh yeah, and one other cool detail that many folks may end up missing...
The flashlight actually casts soft shadows from all objects when you shine it upon them. This doesn't work in EVERY level, but a good chunk of them (darker levels generally). Every item, object, and wall casts a nice soft shadow. It was especially nice when wandering around the snow covered houses later in the game. Strafing along a broken wall looking for chimera while seeing the shadows from the walls move along the floor eerily as you walk. Very nice.