This is a really poor decision as it affects Finn across the entire game which goes completely against the intention you stated which was preventing one phase of one raid from being auto-able.
35% TM gain from popping expose meant you needed 3 exposes to land which meant you needed zFinn, C3PO and 3 rebels. To get past the rng of the base resist chance you needed rebels with very high potency and multi attacks. What you needed to do was simply nerf the TM gain from 35% to 20% or so. The tactic only works for the first topple as she stacks tenacity when the sabres are killed.
Most attacks from 3 rebels is Leia, Ezra and Han which get between 4 and 7 attacks. Given that the team doesn't do a whole load of damage you need them to take a lot of turns without a bad rng run to solo treya in the topple. Nerfing zFinn TM gain to 20-25% would have made the rng low enough that with the best lineup you could have done a good chunk and not have been able to solo the whole thing.
Finn is an old character that is rarely used and needed an update.
Phase three of the sith raid is the most rng-dependant and most hated part of the raid.
This is a step in the wrong direction, and you stop the much-enjoyed ability to solo the tank raid which you -specifically- said you wouldn't do.
Leave the changes to his other abilities (he needed some love) and change his leadership TM gain/opponent reduction to just be a flat 20% TM gain for resistance whenever expose is popped and run a test on p3 to see.
You could probably go up to about 25% and still allow people to do a good chunk whilst not be able to solo it.
