I think people forget to realise that every class has its own strong and weak points.
I myself played SK for only a week before I got bored of it, and no. SK is not a broken class. Each time I fought a human with +12 or better gear, it was an interesting fight, but since my gear was way superior to them I won by ease. And this is the mattering point, that I had +14 mudosa gear with 10+10+9 props, a fighter had to beg Daneos to crit me with every single skill just to trigger my autopot.
Let's break down what SK has.
Bold strike -> Can be easily countered by having anti SK set (antibleed necklace (switch to antifear after you get a bold), and high energy defense.
The pull is usually kept level 1, so the range is low, even if you can cancel a skill of the opponent once, that doesn't do much.
Paralysation also can be easily dodged with the anti SK set.
The AoE stun is cool, but the duration is too low to even argue it to be a game changer skill.
SK has high LP, but that doesn't mean much, since LP doesn't give you LP% or Defense in general, let's not pretend that tanks having +3-4k LP will make a fighter lose.
Namekian crafted and CC armors are based on Energy defense, so to fight a fighter or swordsman (or ultimate-chef) you need high physical defense, which means you need to actually care about gearing properly, now if you can gear properly (without spending your rent money) then you should be able to argue that SK is not a broken class by any means.
Overall : I liked to be able to beat people with a class that I had no experience with, and I also fought other sks in ranked, and majority of the time it all depended on game knowledge. Calling a class broken because it is able to 1 shot you is a bad argument.
SK> PVP/Ranked/Budokai = It is possible to win, if you fill with items that immunize his blows.
SK> Arena =
42% abs+ ultimate buff
59% ant-crit+ pants 33% / title 5% / SK buff 25%.
25k HP+ buffers
4k def+ 18 prop ultimate's buff.
Friends+ who will attack you if you are dumb enough to try to kill a SK in the arena.
Let's see this in practice:
Ultimate can be broken equally, but it does not have that giant amount of anti-crit.