I posted a response similar to this on CS. New engines aren't needed and often bring more problems. What programmers need to do is simply do major upgrades on current software rather than wait for next gen to rebuild and encounter new problems.
I think anytime you go to a new console, the best idea is to port the game over with all of the same features and gameplay and simply improve the graphics which is the number one reason people buy a next gen system. After that first year, then work on the engine and improve gameplay beyond current gen. Continue to work on the engine (and not just tweaks) on a yearly basis.
People act as though current gen AI can't be improved. There is no reason current or next gen AI can't be improved other than the programmers. The 5 year development cycle of consoles has lulled EA into a predictable pattern:
1) They usually build the new engine almost from scratch for a new console which means problems in AI (look how bad NBA Live was at first on the PS2).
2) Over the next 2-3 years, expect gameplay improvements to get back to what the old systems had or have and finally make the game the best they have seen (people are finally happy).
3) The last few years of the system, don't spend any money fixing major gameplay problems or making any core changes (graphics, blocking, etc). Simply tweak the main engine which has grown old and just squeeze every last dollar out of current gen without much spending much effort on anything other than adding minor new features (many non gameplay related).
4) Rinse and repeat.
This isn't all EA's fault and most companies don't rebuild a graphics engine or major AI components in the middle of a console's life. This is due to the ever revolving doors of new systems. With the abilities of the 360 and PS3, hopefully these systems will last longer into the 8-10 year range (doubt it). Only then will the developers want to spend true money redeveloping core components on the same system. If they keep selling us on new systems every five years, a developer doesn't want to spend the resources reprogramming major changes which will only be used for 2-3 years. Heck the Xbox was only out for 4 years before its successor was being sold.