My main bag, an older eTech Weekender Jr., comes in at about 2½#, empty, about 12# packed, and my "personal item", a transformer pad, in it's case with charger and mouse weighs in at less than 5#, so I'm in that 16-17# range.
ETA: I just found this list of rolling bags (some minis) that are all
under 6 pounds
At 6# for your bag, empty, it's going to be difficult to keep its packed weight down to 12#. Think about it. Half the weight is just the bag, nothing you can wear. I take just under 10# in order to keep my 2½# bag to about 12# packed. If I used a 6# rolling bag, the packed weight would be almost 16#.
I'm often amused when I see someone claiming their 6# bag is "ultra-light". To me, 6#is ultra-heavy. Why buy a 6# bag to carry 10# of clothes and stuff?
The advantage of a rolling bag is that you don't have to carry it. The disadvantage is that it's harder to carry when you do have to carry it (like on stairs).
The inconvenience of a rolling bag was certainly made apparent to me on my last trip to Germany, when my partner came along with a rolling bag, which she couldn't easily handle by herself.
We would have to change trains in a station frequently. When we got to the station, I would put on my bag with the shoulder straps. Then I would pick up her bag and carry it to the vestibule by the door. We were often on double decker REs, so there were usually stair to/from the vestibule. I would lift the bag over the gap, deploy the handle, then roll the bag to the stairs to the connecting tunnel. There I would stow the handle and carry the bag down the stairs. If the change was just one platform, I would usually just carry the bag to the next stair, but if the distance in the tunnel was longer, I would re-deploy the handle, roll the bag to the next stairs and stow the handle. I'd carry the bag up the stair, re-deploy the handle, roll the bag to the next train, stow the handle and carry the bag to seats, often up or down stair on the train.
Then I'd take off my bag.