Why not having a community debate about how we would like to see his kit ? It seems devs are wanting to rework him since we could see on Ahnald101 video about TB that he inflicted a new debuff on Han Solo.
I think he's a great toon even now but he is unfinished as the real Darth Vader he should be. First of all, he lacks anti-synergy against rebels. This is what missing in his kit. Then, he's not as powerful as he should be since he's not offering to his squad real synergy. They can only remove TM and their DoTs get infinite but that doesn't bring something to the squad. In fact we could even say that the squad is extremely limited around him and few chars are truly synergizing with him (Sidious and DN). The other are not applying DoTs which is a major issue in this squad. Boba is a great add but he's not an Empire chars so he will not benefit from the TM removal.
What I would do is reworking all his kit and adding 2 Uniques.
Terrifying Swing : Same as now but 50% to inflict DoT, unavoidable and unresistable on Rebels.
Force Crush : nothing to change since I planed to bring something new on Culling Blade.
Culling Blade : Add a bonus effect if target has any buffs : gain 5% TM for each buffs on the target. On a finishing blow grant Despicable Hate.
Despicable Hate : after using any ability grant 100%. While Darth Vader is under this buff, gain 20% offense and stun the target enemy. Consume Despicable Hate after the first ability used by Darth Vader while under this buff.
First Unique :
Rebels Undoing : Each time a rebel enemy gain a buff, call an ally to assist, counter attack or attack any Empire ally, they gain one damage over time effect for 2 turns.
Zeta : Empire allies gain 1%TM per DoTs on ennemies at the end of their turn.
I choose it only applies on Empire since Darth Sidious would gain a huge advantage on Rancor Raid and in Arena with such a possibility of TM gain. It would mean he could gain 100% TM at some point under a zVader lead. It also exclude Boba which would again reduce the possibility of massive TM gain. On the other hand, it would allow TFP to play quite a lot for instance, even though he can't apply DoTs. The main issue I found with this is about TFP gaining constantly 100% TM considering his ability would also help him gain 35% TM. Maybe then, a limitation of DoTs could be done, as well as all buffs and debuffs that stacks ?
Second Unique :
Powerful Hatred : Whenever Darth Vader score a debuff on an already debuffed target, grant them Force Wounds. This effect cannot be resisted or dispelled and last until the target next end of turn.
Force Wounds : Any unit affected by this effect loose 15 speed, 15% damage and reduce their max Health by 15%.
Zeta : This effect is doubled on Light Side characters.
This is a sort of a new debuff but it doesn't last forever. The goal here is to create a breach that could be exploited with a nice burst but that would also be cured by TM gain or speed.
Let me now what are your impression about it, what would you change, etc... or share any ideas on what you would do and why.