According to this quote from the site:
"The designation of S-Grade Augments will be negated in PSO2:NGS and these items will also have modified values that correlate to some extent with the original abilities or stats.
When I was upslotting my Lightweave Sword, I used it's natural S5 Augment to help with the upslotting, and after some time and after seeing what it does, the Flashguard Unleashed Ability doesn't help much since I'm a Hero full time. However I do like the boost it gets when it activates in Hunter, but since NGS is changing things or maybe getting rid of it altogether, I wonder if it might be the best idea for me to keep that ability.
I thought it was but now that I'm unsure if this aug is even going to be there, I wonder if I should replace it with a stat boosting aug after all. Because if it stays that's all the more reason to keep it, since I'm only grinding until I get the Klauz units but, and it'll probably help in NGS, but if it isn't I'm just wasting Aug space for a better one that could probably help better. So now my decision is to either wait until NGS comes out to see what it turns into or just replace it and not worry about it at all. I hope people can get my dilemma about this....