I believe many K-bike riders would say the older K's are more desirable, and the market prices bear that out to an extent. I have an '87 K75 and a '99 K1200RS but to me they are very different bikes each with their own quirks and qualities.
I wouldn't apply the Brick moniker to the transverse K's. They haven't earned it, they don't have the longitudinal brick look to the cylinder head, and I'm just a old fart set in my ways.