I looked at the Diablo III homapage for some time and saw the gameplay video, and i saw some things you could improve, so here we go
Firstly: You've said you would remake all the spells, and i think thats great. But i dont see you need to make too much to the barbarian. You could just remove his stamina, and then add leap. Although it might not be
that east
Ive also found an easy way to make those ghouls climb up the wall, but it might not be too good. You could just set pathing blockers as you already did, and then you could make the ghouls that need to climb up flying units with a fly high on 1. But that would make a problem, which would be that grond units such as the heroes can just walk below them. I dont know if theres any way to fix this.
I also have some improvements for weapons. Now i dont know how you made you're new inventory system, but i have an idea. I guess you've made all weapons one handed in your new system. But maybe it would be better if staffs and such was two-handen and also some large axes, while there also would be some small one handed weapons. I would also suggest you make it so only some races can use two one hand weapons at one time. I dont recall that the caster classes in Diablo II could have two weps at one time. But i dont remember this for sure.
The cultists i dont think really fits into the Diablo III gameplay video. There they summon demons, but in your map they summon skeletons, aint that a little weird? Maybe they should summon
one strong demon instead of two skeletons.
In the gameplay video the hero also gets the archer guards to follow him. So maybe you could make it so there spawn archers for the number of players in the game, and then each player gets one. I think that would be nice

Then you would just have to make sure that they would follow the heroes into the boss areas such as the one with the Skeleton King. Because mongrels dont follow the Witch Doctor in there.
Also, i dint see where that big murloc boss comes from. Maybe you could make some more cultists turning into that lich like demons on that place instead?
After i have played the map many times, ive kinda got tired of the same items. I know you dont have time to make too many new ones, but maybe you could make the drops much more random. Ofcause not the boss drops, and not too powerful items in the start, but i still think its kinda shame with the same and the same and the same items. I would ofc mostly like many new ones, and i know there comes a bunch new ones in v1.18.
Last i would like to talk about something thats been said before. The siege breaker's entry is quite boring :S He just comes running through the gate with very slow speed. Maybe you could make it so that when he enters the camera zooms down like a cinematic, then you set his movementspeed to 999, and let him bash out the gate, and when thats done maybe let him do something nice with cool effects, and then set his movementspeed to normal again.