Working on CMR6 for the X360/PS3/PC, not doing Wii yet though ^_^ It was quite a privillage to be in contact with the PS3 before it was released commercially anywhere in the world. The wireless SIXAXIS controller was quite fun although I still prefer the feel of the x360's controller
To answer your question, there are still large improvements to be made. Nextgen consoles all have multiple cores and HT technology, and parallel programming is something even the most experienced game programmers are having to learn from scratch. Problems involve having to break problems into smaller tasks and most importantly staying thread safe (need to lock+unlock write privilages to resources to stop a read being corrupted by another threads write)
Right now most developers are utilising parallel processing by dedicating entire threads to whole subsystems like Physics/AI/Audio, this is quite wasteful. But with time comes experience, and so improved engineering skills