That wouldn't have solved the texture problem. It wasn't a cartridge storage issue since they could increase that at will when they liked. I remember the OoT cartridge being physically heavier than my others.
The texture problem was that it only had 4KB of texture memory from which it could reference up to 8 textures at a time. Unfortunately, if they used texture lookup tables, this memory dropped to 2KB. :|
This was the major limitation of the system. Various emulation simulations have shown that if the system were given a larger texture memory games could've looked much more rich without increasing polygon count. In hind sight, I can't believe they crippled themselves in such a way. I loved my N64, but I get kinda mad at Nintendo for its implementation. Too many good memories, though. Mario Kart 64, DK64, Zelda OoT, Smash Brothers, Star Fox, Goldeneye, etc.