A lot depends on how original-looking you want your final result to be. I try to keep at least semi-original and I've kept the charcoal canister on my '72 and '86. It doesn't hurt anything and it may aid in the venting of the fuel tank. Some of those fuel tanks have/had 3-4 lines running to them and I don't want a collapsed tank because it wasn't vented.

I'm not sure what you meant by "some other systems". Can you clarify?