I dont think it is an issue of not using our imaginations. In fact, I am not sure that your statement applies to what was being discussed. I think the discussion was about the Crown Knight themselves, the reason there was only one human faction, and the need for another human faction. In lieu of that, I think the discussion was fine.Try this, you may like it:
iMaGiNaTiOn
Y'all had 'em when you wuz kidz wunce.
As for imagination, yeah I had one when I was a kid and still do. It is hard to think that Lego has one human faction for a story line related reason rather than a more practical one. As far was how it works out in "play time" well, I leave that for my daighter to decide... if she even cares. I always just treat them as another human faction which is interelated to all of the factions I have from my childhood (they all live and fight on the same continent so to speak).