A new take on community world-building (editionless)

[IcarusWings]

I was thinking for the celtic thing, so that we can have it as a major aspect without dominating the setting. How about the previous ancient civilisation that's died out, and to which the heroes belonged, was celtic, and a good few of the nations have heavy celtic themes, and the others have at least a few minor ones?

EDIT: And for the wizards and druids thing, in my post I meant all spell-casting, rather than DnD spellcasters. So it still fits with any rpg that has magic.