My recommendation would be to not even use the new EX Buff. Maybe in corner combos, but that's it. It's pure ass now. They removed a strong part of Cutt Kano and replaced it with ass.
With that being said, Slice is better now. With it being -8 on block now it is a much better footsie tool. I used it in the neutral before, but now I'll be throwing it out more often. Very few characters can punish it on reaction now, and on hit you can do a quick run cancel into B31 combo. If they try to attack you land the combo, and most people won't think to armor on reaction to that. After conditioning you can extend the run into 50/50's.
If you're playing characters that you know can't punish it at all, you can use it as a string ender safely now, and on hit apply the same strategy, or use it as bait on block to armor their follow up with EX Ball cancel for full combo.
Slice is better now.