It already exists in the CJK glyphs. A historic misappropriation shouldn't penalize the people who justifiably have a right to it.

Poke around on Google Maps in Kyoto, you'll see _lots_ of swastikas representing temples. It's definitely jarring at first for Western sensibilities, but from India east to the Pacific, people kept using the swastika for what it meant before the Nazis.

(And _since_ they use it -- especially symbolically to mean "temple"! -- it needs to be represented in Unicode.)