Finally, I don't like the idea for Greatswords to be skirmishers...just think it this way:
On the battlefield the courage is constantly tested. Man has to overcome the fear of death (not as easy task as it sounds ) and in order to push yourself fighting on even against impossible odds, you need to rely on your comrade. And that's what greatswords are all about: Companionship overcoming the terror of loss..
Yes, but a greatsword requires tremendous range of motion; you'd be hard pressed to utilize a greatsword worth a damn in such tight blocks.
Can you imagine a world were Greatswords are 'skirmishers'?
Yes. It's called the Real World, circa the 17th century or so. Our army is based off the real-world Landsknecht armies, where two-handed swords were practically their trademark. Greatswords WERE skirmishers that rushed pike units, and broke the heads off so the army's regulars would not be impaled during charges (this is also why pikes later started bringing handgunners with them, to shoot greatswords). So, technically, skirmishing greatswords would be historically accurate.
I understand that the idea behind fantasy is both to suspend disbelief and have fun, and that the nature of fantasy is that things are not the same as the real world. In the Empire, greatswords are the solid defensive blocks, not skirmishers against pikes, and so I am fine with them never gaining skirmish (I understand the difference it makes in their 'feel' and fluff). The fact is, combat is a matter of tactics, and evolving to beat the enemy. Greatswords could easily be skirmishers (or hell, even scouts!) if that evolution made sense compared to their enemies. Whether it DOES or not (or is balanced or not) is a question for the developers, not I.
As for changes to them, I think they're one of the best balanced units in the game I think using them and state troops as a template for all armies would be an excellent way to bring the game back into line. Say "here's the empire state troop, that's a baseline core unit," and build other cores around it, comparing cost and stats to keep it balanced, then do the same with greatswords and special.
Pity we don't have a rare unit that isn't artillery of some kind, or we could have a baseline unit for every slot against which all others could be compared!