Below there are a few new images for ME3 and I am assuming that the delay has to go with something other than the visuals needing work. The game is looking to be extremely beautiful. I find it hard to believe that the delay would be connected to that. I mean, look at how pretty it looks.
So what could be the cause of the delay? Let's speculate for fun. I'm going with the want to add the same 'tech' that Valve put into Portal 2 that allowed for gamers to hop from their PS3s to PCs and back. The difference is that they are somehow making it available to throw the 360 into the mix there. Wouldn't that be something if it was true? You could enjoy the game no matter what you had at your disposal.
Granted that is just my random musing of what the delay could be and nowhere based on any fact. But that would be an awesome feature. You know in case your 360 Red Rings and you want to keep playing on your PC. Then your sister needs your PC to chat with her Facebook boyfriend, so you can then switch to your PS3. Only in a perfect world…