In addition to your excellent ideas on monster abilities and characteristics, I think the tactical combat may also be improved with some changes to the way the attack interface works.
The movement dimension of combat (strafe dance) doesn't seem to be the weak part of tactical combat for me. I think the simplicity of the attack interface leaves some to be desired.
The pace of non-spell attacks seem strange to me, as you just click all the instant attacks as fast as you can then wait for them to pop up again while you strafe around.
If the interface complexity issues that many have reported having with mages can be spread out to the other classes it might help to create more consistent pace of combat, balance the classes from a UI/control perspective, and add some personality and variety to the way different characters attack.
Here's a few ideas in this vein, I'm sure they can be improved upon and may not all work well together. Some might be bad. Permutations welcome.
1) Have a grid of different attacks for all classes (as mages have their rune grid). Some of the options might be things like "attack to the left", "attack to the right", "attack ahead", and/or the skill-based special attacks like Kick, Volley, Bash, Flurry, Rampage, etc. They don't have to be complex rune patterns, and could be an option in addition to the current basic "attack" button. This may not be necessary in conjunction with the next idea either.
2a) For archery and throwing - player holds down right-click/attack to draw the bow and lets go to release an arrow. Attack damage could be related to hold duration, whether it's less damage for instant click attacks or bonus damage for holding the attack (the same thing

.
This approach might also work for thrown/melee weapons, or even spells, e.g. hold right click on the cast button longer = use more mana and bigger fireball, let go to release fireball.
2b) There could be a minimum draw/hold time to fully draw a bow, or ready the throwing axe/hammer, etc. The minimum times could be relatively short and likely dependent on weight of weapon. (Crossbow could on the other hand be instant fire but require holding button to reload)
This seems like it would make some sense that swinging a two hander or throwing an axe would take a moment to ready, but it would also give the player a different sense of feel for different weapons. Right now there is no difference at all in the way I control my fighter and my rogues. I just click the button and they attack. They might as well all be the same 'class' as far as the way I interface with them. At least with a mage there is an actual difference in how the various spells are cast, so my two mages have different rhythms/feel.
3) one might counterbalance the added complexity by making the mage a teeny easier to control since the other classes will now also require some player time/focus to control their attacks. e.g. change fireball and other 3-rune attack spells to just use 2 rune clicks (like frostbolt) since they get cast so many times. Maybe the Greater versions could be 3-rune clicks if that seems too easy.
As a completely tangential comment: I love Mouse gestures, might be some room to consider those too.