Comparing the combat AI of Civ4 to the one of Civ5 (present or future) is tricky, because 1UPT is much, much harder to handle than the SoD design. According to the little information in the announcement, there should be improvements, but I think people have very high (and possibly unrealistic) expectations that even a revised combat AI may not be able to meetn easily.
Personally, I'm nevertheless optimistic and believe that even smaller changes could have substantial impact, and anything I have read or seen from and about Ed Beach indicates that he is a man with expertise, experience and vision.
On a side note, with the MP having improved lately, and the expansion or the next patch presumably improving it further, there are alternatives to the AI. Compared to the state MP was in when Civ5 launched, it's actually quite enjoyable now (but this is strictly based on my experience with games on small/tiny/duel maps and a maximum of four players).