... and even then, I'm pretty sure that the variation on Shadow World is muuuch larger than on Harn, which means that a larger number of contributions simply won't be compatible with each other.
Considering how many house rules there are in RM and, in fact, all the systems, I think that every single RM person going there for ideas knows that he
shall have to adapt any character he wants to use to his own game. Hence why we need a forum, IMO, so that one may ask questions to the original contributor to understand the house rules he used and stuff.
As far as I'm concerned, there's also the language barrier. To be honest, whilst I have literally hundreds of NPCs I'm willing to share, none of them have a character sheet fully in English and even less, a character background story written in English! My idea would be to post them "as they are", then, if someone is interested (using Google Translate or something to get a general idea of the character), I can translate the whole character sheet and/or background story. Considering some have scores of pages, I will surely not translate them until I know for sure it's worth it (because someone is interested)!