Note that things like {{Cite}} and {{trim}} should probably be an extension that adds a parser function, not a template.
Although the overlap between extensions adding parser functions and and templates getting tighter with WikiScripts, in general templates are for re-used wikitext and formatting.
Parser functions / magic words are for computing and logic.
So to share such logic from one wiki to another, one doesn't. One simply installs the same extension.
-- Krinkle