I have found swarm to an incredibly valuable addition to the game, and definitely don't want it to be removed or just added as a skill.  i think it SHOULD be the core of the new battle system.
A few points:
* The AI also has this, it isn't just the player...so it is an even playing field..once the AI is buffed to use it better, though it does pretty well now.
* I agree a dazed, or other incapacitated, unit should not get an attack in the swarm.
* I would be curious how it would play out with a simple change, adding the +1 rule.  As long as the attacking team has one more adjacent unit within the 9-square area (attacked unit plus 8 surrounding squares, see diagram below), the you get the swarm bonus. 
x     x     x
x     o     x
x     x     x
 
As Kraxis, I use a lot of Fortify in a straight line to counter and create swarm.  Three abreast, for example"
x      x     x
As it is, this is dominant, and the only way the AI can (and does) counter this is the shield bash, breaking my line and taking the square, as such
        x
x      o     x
However, as you can see, this would put him in a terrible position if I bring my troops up like this:
x      x     x
x      o     x
So the plus 1 rule, in many ways would hurt the use of shield bash.  But what if, in that circle above, you placed a defender champion with a sword?  hmmm
 
Anyway, with the +1 rule, if I move three pawns abreast, they can counter with:
x     x     x
o     o     o
Now, thjere is no swarm unless someone flanks, adding another:
x     x     x     x
o     o     o
Above, the two enemy 'o' on the right side would be swarmed.
 
I think that alone would make a good system great, by toning it down a litte, but also by adding yet more tactical decision making.