Not sure I'm understanding you correctly, but Warriors are very new ingame and don't have all their functionality yet.
As far as banners specifically, I haven't heard anything about them being dropped. Of course I haven't heard any chat about them at all for some time. Maybe someone else who knows more will come along. If not, it's a good question to add to the March QA question list.
add extra question :
Think you can add ability to the warrior that exists in game now ?
I played the fort area first time today, the Gadai heavy had what looked like an AWESOME warrior ability.
PBAE knockback, stun, snare efffect.
OMG this would make the warrior SO MUCH more fun and unique, and the mechanic is already there working perfectly from the fort Mobs.
it happened a lot, but was a short term but fun mechanic to deal with, and made a lot of sense. should be stamina dependent so you can't overspam it in a fight, but you get a big pull on the tank , nice to blow them apart and let the CC help do their job. i would want a warrior over paladin with that PBAE ae knockback effect.