I strongly second this idea. I know my friends and I have talked about this while playing, and it just seems like a time and effort saving feature. If I have one character without enough gold I can still just pass it to my friend who can pass it to me on my other character, and if I need affinity, I can just pass new enneracts through my stash, but both of those options are rather inefficient.

I don't really see a reason why letting a brand new character have access to those materials would be a problem anyway since the items you can by are level dependent anyway (and by that point you are probably stashing useful items for them). At best I can see them buying the skill gems, but again this can be done on a higher character and passed along if someone really wanted to.