Please bear in mind that I don't wish to belittle anyone's opinions. My opinion probably reflects more on my own lack of insight or time invested than a reflection of the powerset.
But there is one powerset that just reeked with me at the controls. Kinetic Melee/will power.
I tell you the truth, my blasters had more durability than this guy. He was literally like a stick of soft butter in a very warm room against any opponent. He could not hold aggro, which was good, because he could barely handle more than 1 minion at or +1 to his level.
I mean, he really stank. Or I stank at playing and slotting him. I've played tanks, scrappers, brutes with good success, but this guy was just horrible.
In the latter days of CoH, I would read about how great other people thought their kinetic melee toons were, and I'd think, I've got to be missing something. Despite the lack of defense and the lack of resistance, what was really horrid to me were the animations and the sound effects. I fully realize that some players LOVE those effects and animations, but to me, they were cheesy, over the top and so silly I can't handle even thinking about it to this day. Yuck! <shiver>
After a lot of reading, I did learn that Willpower comes into it's own much later than other sets and that slotting is very important. I gave the guy what I though was a pretty good build, but really, numbers wise, it was garbage. I may try it again with a more learned, disciplined approach, but I think the playstyle required to do this build justice is just not for me.