Would the game work better if riot made a 64 bit client instead of 32 bit? Im positive 90% of machines are now 64 bit. Im not saying create just 64 bit, leave 32 bit for 32 bit systems but would 64 bit client make any difference in gameplay?
Not really. It wouldn't hurt to get a 64-bit version in the future, but the impact would be minimal. All it would really do is allow LoL to use more than 4GB RAM.
It's less about how many resources you can use and more about how you use them (optimization).
New Summoner's Rift is a good example. By only rendering viewable terrain and using neat texture tricks they've been able to cut the polygon count by over 20%(?).
