well do you just DROP you bag all the time? How often do you actually slam it into things? Basically, all that padding makes the bag probably 2" bigger in all 3 directions. If you just want the bag to HOLD your gear, not protect it, then that's wasted space/weight.
But this also comes down to how you approach your bags. There are really 2 types of bag usage IMHO, traveling/protection and shooting. When using a bag to travel with and or protect you'll be wanting padding. But when you're just shooting, probably not as much. Look at the thinktank line. Their padded bags run thinner padding than other brands because they're focused on shooting (until you get into their airport line). They even offer some belt bag options w/o any padding at all. The boda is similar, the shootsack is just neoprene etc. So for shooting with something very small on your body, slim or no padding is ideal. This is when you're actively shooting though and the camera is NOT in the bag, just a few lenses accessories are.
Wedding shooters do this a LOT. Then they'll have a pelican or some other massive roller or big shoulder bag for protection, but something like a shootsac for shooting out of (holding the few lenses they're constantly rotating between). When I landscape or shoot my architecture shots that's how I work, I have my camera in my hands or on the tripod. But I'll have the other lens and my filters, level etc in the bag still. In these cases (walking around a really nice house) I prefer to have the smallest bag possible so I don't run into things with it. A vest would also be an option here.
But when I'm driving to and from a shoot I don't really want zero padding when it's in the car. Or when I'm traveling somewhere. This is why some of us end up with a group of bags, not just one. What works for one situation doesn't for another. So you either compromise and have one bag that's OK at a lot of things, or you buy ~5 bags (or more!) that are specialized. I've been down that road before, but have come back to "only" three bags. But I'm working towards better versions of what I have for what I need right now. Something super small/light is perfect for me for the shooting aspect of landscapes/architecture, but the lack of padding is a concern for traveling with it. I'm still toying with the idea though.
Exactly. I've been using unpadded Domke bags for my gear since the early '80s and haven't had any gear damaged in (or out of) the bag due to impact. Your gear is more rugged than you may imagine and the dangers are less than many seem to think.