I want to thank everyone for taking the time to reply to my question. Your comments are going to save me an enormous amount of time ,effort, and probably money. I greatly appreciate it.
Reading all the comments I sense a few things. The K75s were/are still a great bike, but just too small for two people. The K100s, as I have read in books, are very reliable and long lasting, but "buzzy". The K1100, although probably the best bargain going in BMWs, can be pretty hot in the summer. That was a primary reason I switched from airheads with lowers on the fairing. It was either remove them (and the crash bars) every spring and re-attach them every fall, or cook my shins all summer. The K1200s and the K1300s seem like excellent bikes, but a bit short on storage. As mentioned, the flying bricks all use the dry clutch, so there isn't any advantage over the oilhead there.
Taken all around, for the foreseeable future I believe I own, in my R1100RT, the best (for me) all purpose motorcycle. I only want one in the garage, and as people have said, it can do a lot of things well. It hauls a lot, is simple to work on, not too heavy, and is very pleasant to drive. Switching to a K, especially a flying brick style, won't be a revolutionary change in any department. Maybe I am one of those BMW riders that deep down always believes the boxer engine is the best way to go. Perhaps an 1150 sometime, and the R1200 would be great when they get to my price range. The grass always looks greener, and a different motorcycle always looks tempting, but I guess I will stick with what I have, and just enjoy riding it. My thanks to everyone.