Grail Knight First Impression

Played Grail Knight for a couple of hours straight yesterday and I don’t know what to think of him really.
He is strong but besides his ult what’s the real incentive to trade him for a Merc or FK even?
The Ladies quests give all kinds of power/attack speed increases, HP or Stam regen but I don’t really see that being a good trade off for 0 special defense.
The new weapons are kind of weird for me honestly.
First off I knew the Shield and Sword weren’t going to be an option for me, just out of principle, I did give it a try though but never really was a fan of shield in the first place.
The second weapon the longs sword has no real incentive to pick over say an Exe Sword.
Sure you can chain push stab and 2nd heavy for armored enemies or go double long sword and QQ light attack for horde clear but the damage output is abysmal compared to Exe.
Especially the slower push to light/heavy attack chain combo makes it painful to consider.
There is no real incentive to pick any of the new weapons over Krubers other weapons.
After a few rounds I decided to try a few combos and I think Exe and Mace is pretty decent.
FYI I have never been a min-max build guy, I rather play whatever feels fun at the moment if I don’t play higher difficulty than Cata.
I tried around with different talent combos and stuck with the second attack on ult, seems the best trade off to me for boss/elite kiling power.
You can also ledge bosses with it which is neat but still there is this second thought that goes "why would I pick him for ledging over FK really?’’
I knew immediately before trying the horizontal ult attack that it would be better for difficulties with higher enemy density (Onslaught for example)

Still need to play him some more to leave no doubt about his “role” but there is always this second thought doubting his usefulness over FK or Merc or even Huntsman for that matter.
Granted Huntsman is less durable but his damage output I feel over a longer period of time makes more sense than GKs.

I feel like he could use a throwing weapon in the future similar to Slayer.
The throwing weapon could be limited to GK and Huntsman only for balance.

I think I am going to try level 25 talent (incr. push arc and stam regen) today.

The build I have been running:
THP on Stagger
Power Increase on Enemy Kill
Stagger on first hit
50% higher reward on quests
THP refund on damage taken value
Second attack on Ult

Exe Sword: pwr vs chaos, attack speed / swift slaying
Mace: 30% BCR, crit chance / swift slaying
Necklace: +2 Stam, 30% BCR / Barkskin
Charm: pwr vs chaos, attack speed, decanter
Trinket: crit chance, stam regen / grenadier

With this build feels like you hit the sweetspot between mobility and damage output
And in case you run out of stamina, switch to mace you should still have 1 1/2 shields left ontop of 60% BCR.
Not the best trade off in terms of DPS but still a fair middle ground.