As much as I love XI I don't think SNK should or will revisit the tag system ever again. It's not a KOF staple mechanic and its not the most popular or well received, unlike '98, 2002, 2002UM, XIII and XIV and the older games are still active in different parts of the world even competitively(not sure on XIII).
They experimented and it failed just like with '99, 2000 and 2001 striker system with 2001 adding the ability to have more than 1 or none at all. But in the end 2002 went back to its roots and its far more popular and beloved than the 3 games before it, same with XII and XIII after 2003 and XI. XIV unlike the 1st instalments of the 2 sagas before it, is sticking to its roots which I appreciate since they at least tried something new on two occasions.
They need to make all rolls have the same distance across the board. And also increase the walk speed across the board, XIV is not that much slower than XIII I remember seeing the jump and hop frame data of '98 -> XIII -> XIV(Demo) -> XIV Iori and his hop/jump frame data is exactly the same as XIII's, XIV before the console release was sllloooow and that was the main complaint so SNK brought up.
Some characters are off by 1F or so but the difference in speed isn't much, but the walk speed has been decreasing since around 98. But anyway characters like Benimaru, Mai and Leona have better back rolls than most of the cast for no reason. It's obnoxious especially on these characters who are already a bitch to deal with.