This is ridiculous. You haven't actually pointed out a single thing that has been downgraded, you're just linking trailers. I've played the game some 300 hours and nothing I've seen in either of these trailers was downgraded for the final release as far as I can tell. You need to either stop being so vague, or stop being so obtuse.
As for the alpha footage vs final release - again, where is the downgrade? They had the alpha and the final game take place in different lighting situations, but there isn't any downgrade there, it's just the art direction changed slightly. Furthermore, If the alpha can run acceptably, why would they even need to downgrade it in the first place?