In a previous QA they have mentioned adjustments to DRK, although they weren't specific as to what they would be. All they said is they are looking at the entire Darkness kit. (Sorry I'm paraphrasing, but the comment is in 3.05 or 3.02 LL QA if u want to look). The comment was in response to a criticism of Living Dead.
My take of that comment is MP restore. Tinkering with how DRK recovers their MP pool is an adjustment that affects the entire kit.
I think Syphon Strike will remain the same, but they could possibly add a buffing status affect to Syphon or another WS/CD. This new refreshable buff would increase MP regen (like Umbral Ice). And when Darkside is activated, instead of increasing MP regen it simply nullifies Darkside's degen (Nullify not meaning -500mp +500mp, but simply not degen period). It could have a relatively short duration, like just ~10 seconds. The benefit of it though is it would make mechanics more forgiving as DRK. Neverreap 2nd boss if you refresh this buff just before running around to move Totems, you're still losing out on MP+ via Syphons, but at least you've got the ~10 seconds or so where this buff will prevent Darkside MP degeneration. Making it more forgivable.
DRK would still have to toggle Darkside in some situations like Divebombs T5 and other raids. But knowing when to toggle Darkside would be more straight-forward. If this other buff wears off, then deactivate Darkside. In combat it'd almost feel like a second tier of stance dancing.
They could then add the blue flames aura from the demo video to this buff (Something that they also alluded to in LL QAs. They said they would bring the Blue Flames back, but only via a new ability - but 'new' I don't think has to necessarily mean a patach 4.0 or later ability). Visual would play into the meta of Darkside now. You want both Darkside + this new buff up simultaneously. Just my thought on what they're looking at regarding DRK.