Nah, it's alright. I should have pointed out that the above is merely what I read in GW's sources - but as the setting does not have a true consistency, it can well be contradicted in licensed material such as various novels. Unfortunately, the franchise has way less "canon" than most of its fans believe. It certainly wouldn't hurt if you just throw in your ideas - you never know how well they may synch with the spirit of the setting. Or just leave them out altogether, as they don't even belong into the army's usual hierarchy. In terms of rarity, having an "Inquisitor class" would be akin to a "Chapter Master" class. It just doesn't ... feel right if something like this would be playable. But personally, I think you wouldn't even need to have classes like these. The Imperial Guard offers so many possible vocations and roles ... from the basic infantry to heavy weapons teams and snipers to Ogryn auxiliaries (those guys are stronger and tougher than Space Marines!) or elite Grenadiers, from Commissars to Officers. And I'd expect vehicles and artillery to play a very prominent role, too.
The Inquisitors are classed as a "Hero" unit underneath the Imperial Guard infrastructure with most people being able to play as Commissars or Stormtrooper equivalent veterans. It's alot more believable to have a ton of Commissars than Inquisitors because there are IG Regiments entirely comprised of Commissars ie. the Tempestus Scions who are a Stormtrooper division from the Commissariat themselves. GW has sort of lost the lore war when the Horus Heresy started because they allowed the floodgates to be opened regarding Warhammer 40k lore. You can't just go back and take away this much lore unless you want a disaster like the Star Wars universe to happen and wipe thousands upon thousands of fan/author lore from existence. Honestly I doubt the IG will be implemented for a long time after launch because it has so many balance issues, it's a topic great for discussion and debate but little else because there are too many problems involved with implementing them in a game that isn't strategy based with squad type combat as seen in the Dawn of War series.
Honestly, I might even pay to see that happen. Then again, the most recent fluff changes by GW's own hand bother me as well, in particular regarding the "Tempestus Scions". Guess I'm just too stuck in the 2nd-5th edition background. It's what I "grew up" with, and I hate to see it get mutilated and disappear like this.
I, too, would like my Imperial Guard in-game, I am not sure whether they would be playable, because they have said that 'Nids won't be the only NPC's. I hope to play as a Valhallan though.
I would love to see some Imperial Guard, and not just so I can add their skulls to a trophy rack or two, it'd be pretty fun to see a whole massive battle between a chaos force (or any force for that matter) and an Imperial Guard regiment, the scale of slaughter would be soooo much win.
Especially when the Baneblades hit the field. "It's a Baneblade, you can't blame them for running." -Second Lieutenant Marsol Rose
Well the devs never confirmed or denied aerial vehicles. The closest they said was that they would look into it as a post launch upgrade. Probably as like an expansion pack that they would release further down the road.