5D mark III type of improvements with DPP?

Hi there,

Since the 5D mk III mainly seems to improve in JPEG processing rather
than RAW sensor output, I was wondering whether a similar degree of
improvement can also be expected for JPEGs produced by Canon's DPP software.

If this was the case, what would be the chances of getting similar
improvements from DPP for RAW files shot with older cameras?

Thanks&br

Tom