Firstly, thank you for addressing the community and diving into the toxic waters. Thanks for the attempt of a policy, but it only works for newly created characters not recently nerfed characters.
Secondly, i would have to agree with the conditional abilities being over valued. i had Daredevil max 5/4/4 and i hardly ever had the chance to use his purple and never used it to it’s full effect of 5 tiles it was 3 or lower. i would literally sit in fights and mid fight reread his ability to confirm i can’t use it in this fight with 20 
ap just sitting there wasted. i did good in the event to get dd cover and immediately respec’d to 3/5/5. I think you are thinking conditional powers are better then they actually are, i liked the previously mention to change dd purple to be 4000 damage minus 400-500 for each tile destroyed. if that was the case i would most likely try to respec to 5/3/5 cause DD need some consistency to stay relevant with his other 2 abilities being too gimmicky. I also think people are over valuing Health as well other wise hulk and 3* thor would be op, but when i use them they are 
sinks that end my playing, so i have to make strategies to limit the damage to them with out killing my 551 4* wolverine, but it is hard to to get his baby heal off. 3* thor i only get maybe 2-3 games before i need to heal him, hulk can go 3-4 cause he accelerates my wolvine as he gets pummeled. i think it has been a while since hulk got some love why not add a small burst of health when angry goes off 300-500 health, because once it is down to him it is usually a lose. but back to the point.
another question why not buff other 4 stars instead. If one unreleased character is going to break 4thor then i think you did your job poorly. You can use count down tiles to charge objects that blow up or trap tiles for tiles that explode when touched.
this brings me to my final point, are there never going to be 5*? really? if i was managing this game i would want to project some growth in the future and would see them some where on the horizon. if there is going to be 5* then 4 * need to be stronger then 3* and the 4* need to be close to lvl to be able to compete with 5 . I think you did a wonderful job with 4 wolverine and 4* thor pre-nerf, i was disappointed with starlord, elektra, and devil dino. i made some suggestions to make them better
[spoiler]fix nick fury- yellow remove the other Ap requirements, blue leave, purple reduce cost to 10, increase Health for infinity serum in blood 12000 max
fix elektra- strongest color change to black- purple cost 5 start steal 2 for 2 scale up damage 5 cover steal 3,for black auto generate 1 trap per turn. scale up damage at 3 covers can have up to 2, 5 covers can have up to 3; 2/3 current damage for trigger ie max 500-600 damage, red cost reduced to 5
Fix starlord- purple reduce cost to 7 or leave at 10 but does team damage, yellow leave or add minor protect effect on count down time, red split damage 2/3 on cast, 1/3 on tile becomes team damage
fix IW - yellow passive generate a yellow invisibility tile that grants invisiblity to her, cost 7 yellow place a shield around target ally that blocks scaling 2000( maybe more) damage max; collapse of shield deals max 500 damage to all other visible characters , blue 7ap 1 force bubble with each cover reduce by 1 
max 7( maybe 9) force bubble, green 9 shatter random force bubble dealing max 450 max to all non-invisible units destroying 4 tiles around the force bubble if a another force bubble is destroyed it does the same thing; each cover destroys an additional tile around force bubbles.
Fix dino pink remove,add ravenous hunger passive offers 30%(50% @ 5 covers) for ability to retrigger for 30%(50% @ 5 covers) current damage and destroy 1 tile (each cover, max 5) every time one of his abilities has abilities is cast/triggered
fix 4 thor un-nerf
fix xforce if still op[/spoiler]
IF you must insist, and i emphasize must, keep 4* around the abilities of 3* then get rid of the crazy cost of them. 2500 hp for a 3*+ character when there are 3* better then most of the garbage tier 4* and also increase the tile damage of the 4* i was amazed at how long it took me to down a seed team of punisher loaner and 2 1100 health characters with a bad board. but i think there are 5* coming down the line so save us some trouble of buffing the 4*s later as they are now most of them are a joke. also nerf beast.
edited: reread refund policy