I use both hard aluminum boxes and soft bags. Both hold aproximately 38 litres, so i carry the exact same amount of gear whether i use hard or soft bags. Is one better than the other? Not really IMHO, you just need to adapt to the short commings of each one, both have pro's and cons. Can boxes be more dangerous to your legs? I supose they could, depending on design, like sharp corners, where they are placed on the bike, rigidity, etc. Then again i'm sure there's lots of documentation of people breaking their ankles and have no bags what so ever. Bones break when you fall, regardless what bags you have, dress acordingly. Weight? I have read in this thread claims of 20kg-50kg for hard luggage which i find quite exagerated, maybe they were plated in gold and filled with ballast? I build my own boxes and racks to the same standard as your typical TT equipment, they have never weight more than 10-12kg. combined, probably less. When you have soft bags, you will most likely use a rack of some sort to keep your stuff off the exhaust, so the weight you have left over is probably equal to the amount of fuel you will burn in a day, or the food and water you will pack if going into the mountains to go camping, or maybe a lap top and camera/video gear, etc...It's all relative and not an issue IMHO. If you really want to save weight: go to the gym, stay in hotels, forget the lap top, use a point and shoot camera, eat out, buy tires on the way, don't bring tools you don't know how to use and leave the spares with a friend to ship out to you.. This will only leave you your clothes and toiletries, a small bag and very light.
One major disadvantage i find with hard bags is the ability to twist the sub-frame of some bikes in the event of a crash. Soft bags will just self destruct and leave your stuff skattered all over the road behind you, preserving your precious motorcycle kind of like an airgag in a car

. Soft bags are rarely waterproof, easly cut open and are less secure than locked aluminum boxes. Punching a lock makes noise and arouses suspicion, a razor blade is silent.
Aluminum boxes can be way more expensive, but there are cheap options out there if you look hard enough. My Steel Pony's cost me nearly $500 in the end, not cheap for canvas. Both aluminum boxes and soft bags are equally fixible, whether you need a hammer, drill and rivets, or a needle and thread, all of which are available anywhere in the world.
Finally, to the OP, please forgive all the childish bantering going on in this thread, instigated and followed through yet again by the same group of people. This got old along time ago, and i can't tell you how many interesting threads have been ruined by this same group, arguing with each other and taking things WAY

. Give it a rest guy's, we're all tired of it. Take it to the Bar or go to Joe Mama.