Haha hopefully you're just trolling poorly.

Be kind of sad if you didn't actually take a moment to check the timing on events before saying that.

I crunched the numbers after this attempt (with and without poison) and the attack speeds with different ASI setups, and DVS is actually just a superior weapon overall for that fight. It even does slightly more DPS than a flourish, keeps a poison going, and has very good control against a target that large and slow. You can either swing and aim yourself in a path around the boss, basically moving (and avoiding his swing attack when it sets up) and damaging the whole time. Just melee'ing a circle around a giant target. The other thing is if you have auto target to a hotkey, and you're behind him, you can use auto target and stabilize yourself in one spot and just drill away.

The ability to constantly weave a circle around him while doing damage though has a lot versatility. The flourish is a good second choice, but the major downside (and you can see Exile run into once or twice) is the final thrust can put you in harms way unexpectedly if the boss moves or you glance off target by a hair. I haven't had the luxury of testing out a CTR max on a Flourish, but doing a well aimed charge attack over and over might be very competitive in damage to a FoV. Just without setting yourself on fire. XD

DVS outside of this encounter though is kinda meh as a T3 weapon, since damage flavors and mob mechanics make many other weapons far more efficient/effective.

To answer your other question, poison is a great thing usually for fast and furious weapons, and the odd thing like the charge attack on a Blitz Needle. It's 15 rapid shots, so 15 small bonus damages add up to really good extra damage If everyone carries some poison vials you can probably get some decent up time on poisons, but it would be good to have a person or two using a DVS so you don't even have to bother with vial throwing. DVS lands a strong poison, so it has really nice lasting power.

Thanks Volt, as Ex said we only coordinated the predictable points, which are usually the phase openers. IE - go to this corner for your water, and I did all the water shots on masks while they charged up FoVs. Originally planned this cause I have a CTR V.H. FoV, but turns out you really don't need it since it dies almost as you get the charge going, so I ended up just getting in with the DVS as fast as I could before it popped.

You can't plan too much, and you'll even see a really nice recovery in there where Exile turns an "oh s#*!" moment into an "oh yeah" one. XD (We do take some hits there, but intentionally to keep the aggressive pace going) Though in the last phase ex shields up and gets pushed by a fire orb into the boss swing, and his shield durability didn't hold. It pushed him towards the fountain and stunned him. He capped, and used the water to knock out the last two orbs at just the most ideal spot and time.

We're all really good at reading each other and reacting to what's going on, so if he was stuck into some assignment there it would've probably would've caused problems to pile up and interfere with the other people's assignments. Lots of randomness in that fight, so you just have to wing some of it.