Well, everything seems about right except for the Elementalist, if you can tank the dmg from the Elements, just go straight for the Elementalist himself, they never see it coming, with decent hr acc, u can smite and then it's pretty much all over.
And warmaster pvp is way exaggerated, we are quite ok, if u know how to use us. The key is to take advantage on our advantages, like our high hp mainly and our stun.
Lastly, bare in mind that the general Titan class and yes, unfortunately the Knight class as well regardless of dual class, gets much stronger in PvP outside arena. This is because of our defence is no longer capped as it is in arena. There is a 2k defence cap in arena, so the classes with low def such as Rogue, Healer, Mage, Sorceror and Night Shadow can still fill up the 2k def cap, which evens out the playing field on def, but in actual fact, a Titan or a Knight's def is usually 2x or sometimes even 3x in the case of TKs the def of these classes.