imo, fwiw, rofl, I think returning an ember-extended array is misleading to later code that may or may not receive data modified by this logical branch (someone may write code using `data` after this logic expecting an ember array, but that may not be a guarantee in all cases).

If we really wanted to add observers to raw server data, should should have an up-front step that wraps all server data in extended versions, but I don't think that is pragmatic or really what anyone wants.