I thought it would be really cool to see a class capable of casting different types of AOE buffs (and attacks) on the battlefield.

A little different from the AOE we currently have.

an orb you can place on the battlefield that (like what is seen in the opening video) that protect those inside from either magical or physical attacks. (can be one for each, or one that does all)

this can be used to protect allies form say breath damage. maybe make these wear quick.

side effect of using a spell like this is that it could generate massive amounts of short term hate which dissipates when attacked. Can stand in the bubble to protect yourself.
Also, you could have it so that mp is drained during the duration of the attack.

Another would be a physical barrier.
This could be cast around enemies or around players.
What this does is prevents movement through the barrier.
This can be used strategically in larger battles to isolate players with a select few enemies, and can also be used to trap enemies for short durations.

Barriers would have a health pool and drain MP. barriers could wear after taking a certain amount of damage or if the caster is killed. (maybe even attacks that select enemies use make these collapse)

Attack type AOE

Something like burn, but maybe more powerful.
Cast AOE on a spot that causes damage every second for a few seconds till it dissipates. Enemies (or players) in the center would receive increased damage and keep receiving damage until they fled the AOE.

I thought these would be super cool, make battle extremely dynamic on both sides.
I can see there would be some balancing issued, along with great costs to enemy AI as well as the cost of design, but hey, why not put it out there.