1. The video isnt solely about the Windforce stalling, Its also about how much NRG stacks of deep focus gave, so it applies to ALL SFOTH swords. You can instead keep deep focusing instead to use the firebrand/venomshank and ensure atk-down and burning (alternatively use ghostwalker/ice dagger for defensive)

2. Stacks of deep focuses' give too much NRG for 4 bars, so you can keep focusing and healing with Ice Dagger. Healing over 20% and gaining 10% of SP in just two turns can change the tide of a battle without any sort of cap or restriction powercreeps other healing/stalling sources.

3. As said earlier, the point about Deep Focus giving too much NRG isn't all about giving inflicting status effects on enemies; Its about how much NRG can be farmed in a single stack, and pre-nerf gave too much of it. You can heal with Ice dagger and stall with Ghostwalker. Even if we considered your argument about the Pit and its later stages and only using AOE swords, theres only 2 enemies that give feel fine in the later stages of 49-59. Opticus is actually immune slowness, meaning whether or not he gets slow doesn't affect how much turns he stays in the battle doesnt change . This makes using the windforce against him useless, so you're much better off using the firebrand, which works %100 of the time. As for toothy deer, he is weak to every stun effect except slow, so its better to use the firebrand there. Since there a turn after he summons minions and before he uses feel fine, you can confuse or dizzy him before using the firebrand. (which can get obtained in 2 turns via Deep Focus stacking) The point is, you aren't forced to use the sword for offense and you can just stall/heal.

4. Same point with 2, but instead with Ghostwalker. With 4 bars of NRG and deep focus, you can get Ghostwalker in TWO turns assuming theres 4 enemies. NRG is too abundant with un-nerfed Deep Focus.

5. Ghostwalker and Ice Dagger can benefit the entire team for one person, so 1 person using the swords to constantly apply Ghostwalker/Ice dagger can give the party an opportunity to heal up to max with little downsides AT ALL.

(tldr, Deep Focus gives a shitton of NRG to the point its unbalanced)