Tonight I went crazy and tried Ventari in wvw roaming. My build was apothecary + dire with mallyx and ventari renegade. My build was far from perfect so i am gonna skip that part and come to the point. First of all ventari works more than i imagined. Especially in this condi heavy roaming meta (and against ranged opponents) it really worked "enough" (died sooooo many times) for me to roam. But there are few issues:
-Ventari needs a stunbreak (duh)
-Tablet radius should increase to 305 radius to cover the dodge range at least (from one end to other). 300 is the dodge range as far as i know so +5 can cover it well enough.
-Ventari's Will cd should be reduced to 2 seconds.
-Purifying essence cd should be reduced to 3 seconds as it already costs too much energy to use the tablet.
-Natural Harmony is meh but you can buff it via traits.
-Ventari's Will needs a buff. The regen was really good and important but now without any boons Ventari can only give alacrity, which really does so little for your sustain. And it should be faster.
-Energy expulsion should remove conditions not 1 per 10 energy but 1 per 8 energy. This way you can use it more fluintly in the combat. But i am not sure of this as there is already too much cc in the game.
The biggest problem is the healing orbs. They are not worth it, really. I don't know what was the intention for implementing those but come on, they suck in wvw.
Compared to other bruisers/sustain fighters I admit that it is harder to play, gives less than others and weaker. It can never be top tier but can be effective enough to be fun with some changes.