Well,
I still own a few mechanical watches, inspite of the fact that the Ronald McDonald watch that comes for free in a kid's happy meal will actually keep better time. But, I have been falling out of love with sidelock double guns for a long time, mostly for the same reasons detailed in your list above. No doubt, the examples that passed my way had lived long lives before they came to me, but, they were, to a one, money pits.
I consider the A&D boxlock a huge improvement on any of the better known hammerless sidelock designs, which, were simply hammer guns with the hammers on the inside.
I keep waiting for lightning bolts to hit me when I opine this, but, they haven't, so far.

Best,
Ted