Well, I didn't have any problems with Battlemage as my second spec. Combine the two and AW is both nigh invulnerable and capable of harming all surrounding enemies continuously. Laughable ease 
Indeed, but even the basic Mage back then had access to healing.
In other words, Arcane Warrior was a thing of Origins. If it was made into Inquisition with a more advanced inovative and new gameplay style, it would be something like the Knight Enchanter.
Basically they are the same thing, just different lore, and different mechanics. Both however can go melee to fight, and both can weay heavy armor and have abilities that help them tank.
They do however play very differently.
Also Battlemage was added afterwards. The strongest combination was AW-SH-BM. (BM=battlemage)
I am pretty sure we're gonna see people soloing this on nightmare with a lot of classes/specs.