Also, in the vein of the OP, there is a strange discrepancy, Space Marines are a race, within that race you have chapters, each with their own commanders and special rules and I assume each chapter has a selection of classes to choose from. Looking at the Orks, you only have the race and then each clan is a class role (and as far as I can see no Snakebite feral Orks). It seems that they are treating each SM chapter as a race in it's own right but not doing the same with Orks (I can't speak for the other races as I've not read up on them so much).
I think you are over thinking things. Each clan of Orks is NOT a class. They just have a preferred type of tactics/way of fighting. JUST like the space marine chapters have.
Not really. IWI i started is nothing about getting Guard in and i'm only talking about that in Threads that have that as Topic.
I hope you're right, I do hope we get to see warbands composing of the cult of speed and warbands from individual clans.