Nope. Tag mode imo wasn't really a relevant mode once DOA5 came out, it's not balanced or competitive at all. You can do ridiculously long combos that take no skill, go for ridiculous set ups that already will do big damage before the launch, and the gravity is ridiculous as well since you can perform overly long combos that once again take no skill to perform. The mode in DOA5 is basically a scramble to get the opponent into a stun and once they're in the air, you're just do a juggle, switch out and juggle with the tag partner, and then rinse and repeat.
If it returns they should balance it since with DOA6's new mechanics and such, it would be a broken brain dead mode. You would be able to do so much ridiculous set ups unless they toned down fatal rushes and fatal stuns for that mode and unless both characters shared a meter bar since you would be able to do a stun set up, launch into a bound, break blow cancel, switch characters(if you hadn't already done that), and go for another stun set up, launch into a bound, and then finish with a break blow xD
That doesn't seem like a fun time imo, if it returns(which I doubt unless they make a DOA6 Ultimate since tag mode I imagine would be a good couple of GB) they'll have to balance it since it doesn't seem viable or balanced with DOA6's current mechanics