Is this not an awfully convoluted means to achieve a simple end?
Well that's a matter of opinion.

Obviously I don't think its that convoluted, but then again I designed it so I'd better have a pretty clear understanding of how it works!

I think its a radical departure from the status quo, but that doesn't make it intrinsically bad.
I think having a clear-cut order of "this unit who's internal cohesion has completely broken down" is no more convoluted than how the Hold order on a unit that has just rallied (i.e. "It's Hold except it's a special Hold for this turn because the unit can't do anything").
To me it seems simple: if you're engaged, you rout. If you're unengaged, you're Disrupted. Then you look up Disrupted to see the effects. But again, I wrote it.

I've always been inclined to think that the way of creating a combined arms effect is to provide combat units a bonus when supported by archery. I have no idea how to achieve that but I can't help but think that adding new status/phases is not the way to go about it.
Yeah, neither do we and we've been kicking around ideas for almost 3 months now.
We originally started in the same place as you: give a bonus only to the build that is perceived as weak, i.e. combined arms. However this runs into two problems.
First, any bonus you give a combined arms ranged unit will almost certainly also benefit a stand and shoot. We worked with bonus as short range, bonuses while archers are backing up enagged unit, etc, but all of those would benefit stand and shoot as well. So the relative power stayed the same: stand and shoot was better than combined arms shooting. So any bump to combined arms would really just be making stand and shoot stronger vis a vie close & hose, which was not the intent.
Second, when you come down to it, there is no such thing as Stand & Shoot or Combined Arms. There is only "who has more shooting." The player with more shooting should always stand and shoot and the player with less should always close with the other guy. You can twist and tweak all you want to encourage combined arms, but in the end you'll run into the simple fact that
you can achieve decisive results from shooting alone.
So to us the solution seemed was change that underlying fact. If you cannot achieve decisive results (i.e. rout someone) by shooting alone, then just standing and shooting is a poor strategy. You
have to engage in melee at some point.
From there we introduced little bonuses into shooting, since we'd basically just nerfed the hell out of it: shooting goes first and there is no penalty for shooting into melee. Neither of which is a big bonus, unless you're pairing shooting with something.
I dunno if that convinces you, but at least I hope I'm showing how we've done our due diligence on this one.
I'm lukewarm to this, but I do think that if a Disrupted unit is engaged it should rout automatically.
Originally we did that, but it just felt wrong. We were of the opinion that if a 300 pt unit blows a Cge 13 and then gets charged by a 70 pt unit that they just rout automatically (and possibly be destroyed) was just a little silly. Our opinion was that even though those Celestial Guard had ceased to be a unit and more a rabble, it still was a rabble of High Elf Paladins, which does have some intrinsic fighting ability.