Mr Incredible was the most effective, but then that became a double-edged sword becuase that made friend campaigns a nightmare.
Least effective has to be Sully and Felix, very little was done to address the core issues of them. Namely, they are way to fragile for tanks, especially ones in the frontline
Well I agree with the peeps around here in the sense that Mr.Incredibleās refresh made him way stronger than what he was. It was very effective and hes a beast once he gets below the 50% hp mark. Howeverā¦this makes him very hard to defeat in friend campaigns if your not ready. As well as stitchās refresh, which made him better in dealing more damage, and slowing people down.
The only ones that were least effective was felix and Sully. Felix wellā¦the refresh didnāt do much other than give him a tiny boostā¦it barely made a difference for the fact that he almost always gets one shot, no matter what. And his skills, like blinding and stunning are very weak and so brief that it barely does anything to the other team.
My suggestion to fix him would make his stuns and blinds last longer. His white skill damage? Increase it. The stun should be increased from 5 seconds to 12, to make it count and it least be a little more effective.
As for his blue skill, make it blind, charm or stun enemies for 9 seconds.
His purple skill should also grant +max hp and +basic damage, +reality. This is to make his purple skill more effective in supporting the team and helping it in the background.
As for Sully, I liked the refresh, especially on the disks, since it made them a bit better. Howeverā¦that refresh didnāt help sully much.
Yes he heals, but I feel like he canāt deal a lot of damage, and canāt use his skills as much as he should be able to.
So heres my suggestions again (xD).
Since heās in the scare category, I feel like he should make use of that. The problem is that the only way he uses it, is in his white and purple skill.
So, for his white skill, increase the damage and make him scare enemies for 20 seconds, so the team can crit more against enemies.
For his green skill, theres not much to do, except increase how much he heals, (since allies get more if u have woody disk on) and give him a 5-8 seconds of invincibility, since Iāve noticed that hes sometimes stunned or freezed when he heals, and then he diesā¦which made the heal useless.
For his blue skill, increase the damage, and make the toys scare or stun enemies for 10 seconds.
His purple skill is kind of like felix. However, like felix, I want him to be able to support his team more, just like he does with his green and white skill. In addition to getting more skill power when enemies are scared, he should also passively give allies and himself: +Max HP, +Skill Power, +Basic Damage +Reality. (Since he gains some skill power when an enemy is scared for any source, I think this would help the team as a whole.)
And of course, buff his HP, basic damage and skill power, as well as how much skill power he gets from the disks, andā¦maybe add +Max Hp to the disks, to help sully even more.
Anywho, these are my thoughts about the refreshes.
I hope you refresh these heroes and others soon 
The downside to hero refreshes that Iāve seen is that, after just a couple of months, power creep tends to render them nearly pointless. Jack Sparrow is probably the best case in point: for the first month after his refresh, he was actually a top-tier hero; for another month or two afterwards, he was still strong enough to be seen on some arena teams and many coliseum teams; and after that he vanished from the scene again, replaced by newer heroes whose stats and abilities put his to shame.
Keeping that in mind, Iād actually argue the most effective refresh so far has been Finnick; heās not seen in arena because heās really squishy, but I see him fairly often in coliseum teams, as his improved buffs and added ability to stun made him a viable control hero. Elsaās refresh is recent enough that Iām still not sure of its staying power, but so far itās been a good one as well, though I suspect thatās largely due to her red skill. Mr. Incredibleās refresh looks like it might be as successful as Finnickās in terms of promoting a nearly-ignored hero to one seen fairly often in coliseum. And Stitch, of course, is awesome after his refresh, but thatās because he was a really good, if ignored, hero beforehand, so I donāt think it really counts.
The least effective refreshes were for Maui and Hiro; neither one really gained anything new, just some improved stats, and of all the heroes that have been refreshed, theyāre the only ones I really never noticed getting used more often, even immediately after their refresh. (Granted, I think Hiroās pretty good anyway, almost as good as pre-refresh Stitch.)
EDIT: I almost forgot to mention: Personally, Iād really love to see at least one hero refresh per new hero added to the game. This way, people who canāt afford to acquire and level up more than one hero a month still have a shot at improving their teams enough to keep the game fun, instead of cringing every time new heroes are announced knowing full well theyāll fall that much further behind.