ok the issue is this, the original engine could run on 360/PS3 and than upscale the same engine for PS4/XB1 part of the issues with destiny is that the old engine was holding it back to the current generation, there was not enough memory on ps3/360 to add as much as they have added. Once rise of iron came out it added alot more shader effects to the game cause its not avail on old consoles. For Bungie to make a change right now, the engine is so old that they have to DECOMPILE the entire game which takes a day to do than they can make whatever changes, add dlc etc to the game than they have to recompile the game. that is not optimal for the current generation. I do think the engine would have to change and be upgraded so changes can be made easier for the DEVS to implement.