I have the solution about The Serpent rebalancing
It may sound crazy, but Kabam should buff The Serpent even more.
He's the fear guy. Your champions shouldn't have the courage to hit him. During the first 30 seconds you get rooted because you're paralyzed by fear.
He should have a second life, Nick Fury does and no one complains, why can't the supposed best defender in the game have one? And both should activate immunity to death, regeneration and power gain.
The fear debuff he places on SP1 should be passive, so no one can take advantage of it to regenerate with willpower.
His SP3 should ignore damage reduction.
The Serpent imposes fear, so you should lose power when you hit him.
Finally, you should be paralyzed by fear when The Serpent shows his abilities. After activating a special, you will be rooted until the end of the special.