Though the golden rule is still important: When in doubt, probably should nerf.
And there is a point where if you nerf too much it starts to become an issue of your character not having a leg to stand on which severely reduces their effectiveness in combat. Right now Senti is nerfed and even has cool-downs applied so he can't spam his moves and end a fight in a ridiculous amount of fashion. He's still OP as all get-out, but that doesn't mean he's undefeatable by any means. Also, SL's hypno ball was pretty OP itself. >_>
On a more serious note though the investment into CC and HP seems to only make that character all the more OP. One of the things I commented on was how Senti couldn't be allowed to attain Elite status since the gain would only to serve to set him at a higher bar than most of the mistresses on the site. The issue here is when you create a decent character with lots of potential and who can handle themselves in 1v1 effectively, the entire thing falls into a power creep. (See: tropes-Power Creep) The problem with a power creep is in most cases is that it occurs in a manner that leaves no doubt as to how "fair" it is to everyone EXCEPT the people who aren't prepared/conscious of it's existence.
One of the major concerns that came up a while back was that a Mistress was too OP to have a fair battle and that if someone was ambitious (and possibly cheeky) they could just stun-lock the mistress and tally up victories like that until they could gain a sufficient enough power bonus to stand toe-to-toe with your average mistress. As a means to counter both problems the application of effects required the range be lowered to an amount that permitted a fair chance to break and that mistresses take a power nerf in terms of HP and (possibly?) range vs damage ratios. I'm not whining nor defending this position but simply using it as an example of how we handled the power creep last time.
So now a hero can essentially power through a single mistress if built properly but at the same time both sides have a fair chance so long as the rolls they throw aren't bad. My concern is whether or not the elite rank is maybe poised too low for a fair balance or if it's meant to create a situation where a single hero could outgun a single mistress at a certain point.