Some great ideas in this thread.
With the introduction of Rift magic, many spells have been altered in various schools of magic (as explained by Your Trainer in the way of the rift mage quest).
I would like to see a new spec for each class.
Personally i would like to see
Spirit Warrior-
As the breach has opened, surely it is possible to come across a rare spirit that wants to assist you in your quest to restore balance to the world. This spec could open some great dialogue with Cole, Solas, Cassandra and Dorian. Even Varric, he could be wary because of Anders.
I would like to see skills that make the Spirit Warrior a sort of medium between Templar, Knight enchanter.
Maybe a buff that imbues your weapon with spirit damage for X seconds.
Soulbrand perhaps?
Another ability could be a pulse of spirit energy that knocks back enemies. Kind of like a more offensive mind blast.
Another ability ability could be called spirit strike, where the spirit splits from you momentarily and you and the spirit do a double strike on an enemy.
the focus ability could be granting you and the party bonuses to attack and the fade cloak ability.for X seconds. To avoid being OP, i would leave it as fade cloak, not include the decloaking blast upgrade.
Keeper
As there is no nature damage in dragon age inquisition, we do have poison damage, as such, i believe keeper spells should involve dealing powerful poison DOT, and spells that involve hindering enemies movement.
We also know that some keepers can shapeshift, and i would like that to be implemented too.
Skills could include
Glyph of entanglement. When an enemy stumbles on to the glyph, poisonous vines erupt from the ground, entangling the enemy for X seconds and dealing X poison damage.
Cloak of nature- the keeper surrounds themselves with the power of nature. For X seconds, the keeper hampers enemy movement with vines surrounding the keeper, and the keeper gains a armor bonus. Upgraded, this spell could include poison DOT for enemies within the aura.
Strength of the bear- For X seconds your shape becomes that of a great bear, your armor and attack are increased, and with an upgrade gives your blows a X %chance to knockback an enemy.
the focus could be Natures vengeance, where ALL enemies within the spells radius are speared by roots that erupt from the ground.
As for Rogue, i have seen many who would like a support rogue. As such, a Bard with access to Songs to buff the party could be quite valuable.
Probably not everyone's cup of tea, but just thought id share my thoughts