I don't know if you were one of those people but in response to this point, the Arcane Warrior's melee was never on par with warriors or rogues. At best they had a reasonably strong auto-attack that was overshadowed by the need to constantly sheath their weapon to cast the majority of spells. Warriors had a wide range of knockdown, stun, and debuff weapon attacks, and Rogues had all of this plus backstabs, CUN based damage bonuses, and bleed damage. An AW couldn't even use Mind Blast without first putting their weapons away, which broke the momentum of combat and added ~2 seconds to casting time. I don't think this is a fair comparison. The true advantages of the Arcane Warrior were the defensive abilities: Shimmering Shield and Fade Shroud. While those two sustains were admittedly OP, the AW melee abilities were actually much worse than those of a trained Warrior or Rogue.
I will, however agree with your point that this 8 skill setup will greatly alter the playstyles between KEs and other mages. I think there were 3 active skills on the KE tree that we last saw? Add to that the dodge ability and we're already at half the spell limit. I suppose you could take the spec for the passives and still play as a caster like the DA:O AW, but I highly doubt that will be a useful strategy this time around...
Well, most of what I'm about to say is theoretical because I never played as an Arcane Warrior, but I think the problem with that class was more that it had little identity of its own.
Shapeshifter could allow the mage to change shape, and no other class could do that. Spirit Healers had access to additional healing spells that non-specialized mages couldn't cast. Blood mage had bucket-loads of flavor (and blood!) as well as alternative spell fuel and a mix of powerful control/damage abilities.
Arcane Warrior, on the other hand, mostly felt like a way to cast spells as usual while doing basic attacks with heavy weapons and wearing heavy armor. It was a sort of clumsy link between two classes, but it didn't stand on its own.
What I would like to see from a class like that (maybe Knight Enchanter) is a mage who wears armor, sure, but also attacks and fights, perhaps at close range, in a uniquely magical wayl. This could include neat staff melee combos. Moves like...
Staff Assault: You deal 200% weapon damage per hit in a 3 hit combo at melee range with your staff. Upgrade it so that it ends with a fourth thrust of pure force (imagine a force push) that stuns the target and knocks them back.
Shockwave: You slam your staff into the ground and destabilize foes near you; foes within 5 meters are stunned for 5 seconds and suffer a 25% penalty to Armor for 10 seconds.
Blades of Force: You conjure blades made of pure energy that surround you and harrass your attackers. Anyone in melee range takes 100% weapon damage every time they attack you for 10 seconds.
Implosive Force: You unleash a massive wave of energy that pulls all enemies within range towards you. All enemies within 10 meters are pulled towards you.
And you could have passives like:
Arcane Combatant: You have learned to withstand the rigors of battle with the skill of a warrior. You can wear heavier armor and gain a 10% bonus to Armor.
Shimmering Shield: Your combat hardiness now extends to the attacks of other mages. Whenever your mana is full, you gain 25% resistance to hostile spells (like a dwarf).
Something like that. That's really, really rough, but those are ideas I'd have for a class like this.