If you were to have Requiem Angel and say 4-5 non-spirit tokens on the battlefield and then cast Planar Cleansing would you get 5-6 spirits after all is said and done? This strikes me as though it would work in the same fashion as how Blood Artist is being used for board clears these days.

If so, why not run a deck around making totally inconsequential tokens and then wipe the board to give yourself the MAJOR advantage with spirits while they have nothing?

Yes, the combo works. However, you would only get 4-5 spirit tokens after the board wipe because Requiem Angel doesn't count itself. Also it would be better as a side strategy to a token deck used in the typical way.

Very cool. Talk about a board-wipe deterrent.