Part of the motivation for thinking along the lines of an easier way to transport panniers etc. off the bicycle started for me back in 2003 when I went to Europe for 3 weeks ... and it comes up every time I travel with panniers.
There I am in airports, train stations, bus stations, etc., watching people of all shapes and sizes and physical abilities trotting around pulling their suitcases with wheels. Meanwhile, there I am hoping for some sort of trolley so I can transport my panniers etc. without having to lug them around. Suitcases have progressed to be easily transportable ... but cycling luggage hasn't.
And how many threads have their been in this forum about how to transport all the stuff we bring with us on a tour in an airport. You've got the bicycle box which holds some stuff (and isn't particularly easy to cart around either), and then you need something else to carry the rest. I've used a laundry bag with shoulder strap, and then folded the laundry bag up and carried it with me, using it as a part of a pillow. That worked to some degree but wasn't ideal. On this trip, we've used cardboard boxes, and eventually threw them away when they disintegrated, but again, not ideal for carting around an airport. You do need a trolley. We've also used a sort of woven plastic-y bag with a zipper and handles ... a bit easier to transport than the cardboard boxes, but not terribly sturdy. Others have used various sorts of duffle bags or thrift store suitcases which they've disposed of later.
Why not some sort of luggage set which can be clicked together into one unit, with wheels and handle, for air travel and ease of transport off the bicycle ... which can then be detached into individual pieces and attached to the rack of a bicycle?