These are all design issues, as stated, and for the reasons stated.
Jules V. has some helpful tips here somewhere about how to shore up the lid handle so that it doesn't chip the paint like that. It involves adding one or more SS washers, so that the weight of the lid is distributed better across the handle connections.
"Friction fit" means the old kettle legs could not move due to the friction of them being pounded into the leg sockets. It's the only thing that kept them attached to the bowl, and the also the reason why on old kettles, you see legs falling out. What happens is that the legs get bent where they insert into the sockets, the friction is then gone, and the leg falls out ... which by that way, won't happen on yours, since it does not rely on friction to secure the leg to the socket.
Glass half empty, half full. Take your pick.
The sweeps have been that way since their introduction in the 1980s. It's related to the distance between leg sockets, which limits the travel the sweeps' handle can move (for the chosen blade design, as you noted.) A long handle brush helps scoot the rest of the ash down if it's a worry.