Maybe, but I want tag feature back.
As, err, ok as Tag was in XI, I can't imagine a Tag KoF ever being a truly wonderful KOF... a GOOD one, yeah, but a standout? It just doesn't seem to work that way! 
Every lazy, or "flat" element that tag brought to XI, makes XIII all the greater for me, as it corrected a lot of those movement, sound, and pacing issues.
Tag should definitely at least be an optional feature in the Ash Saga dream match, however. It was a big part of this saga, so it does deserve to be represented.
Hey, I thought KOF XI was pretty great. I definitely agree on its graphical "flat"-ness, though. But that doesn't mean you couldn't make a KOF game with excellent movement, sound, pacing AND tagging.
I'd also love to see tag return at some point. If it did, I'd prefer to have your teammates standing in the background (a la KOF94-98) rather than simply off-screen. Graphically, I want tagging to look similar to plane-shifting from Fatal Fury, or how classic KOFs had your teammates coming in to save you when stunned. I think this could keep the characters "weighted" and prevent them from looking as "flat" as in XI. (At least, if I understood what you meant by flat.)
Also, I don't think including tagging as an optional feature is a good idea. It would be much more likely to be buggy and unbalanced. Besides, it's much easier to turn a tagging game into a 3v3 format, rather than take a 3v3 game and tack-on tagging. /OT
Continuation to the conslusion 2011 series, this time, Ikari and Fatal Fury teams!
http://www.youtube.com/watch?v=Pz62shfWe-g#
I love this series. Haregoro proves again that Joe is a killing machine. Leona shows off a Takuma-specific 100%. Ralf's HD corner juggle was also really good. I hardly see Ralf use HD, but it seemed really practical. Just qcb+A / AC and qcf+P (A? C?) a lot.