Why would Houston rather have Ray than AI?
I don't think they would, but I'll play Devil's advocate to give myself false hope.
The Rockets get very low efficiency scoring from their wings. Ariza, Battier and Budinger are shooting at or below 40%. This dramatically reduces the effectiveness of Aaron Brooks, the classic drive and kick PG, and shifts much of the playmaking role on Trevor Ariza, who's much better suited to playing off the ball. Adding Ray would significantly enhance Brooks and Ariza's games.
That might be preferable to adding another non-shooting wing.
Ray would certainly give Houston a lot more than TMac is.