That's a decent breakdown of them. there are quite a few sharp edges, some need a bit of buffing, mainly those that are in contact with the bars, to prevent point pressure.
The calipers have a rough finish on the inside around the pistons. Although I never thought it would be that much of a problem. they're cheap brakes, it's a hidden area.
he reported caliper flex is a bit worrying, can't say I'd noticed it in use, but....I'd not really looked. I'll need to keep an eye on that, if it looks like it's flexing more than it should I'll def need to watch out for cracking.
The comment about the lever piston diameter is interesting, admittedly it's not something I'd considered as most manufacturers for their mainstream brakes, I thought got piston seals in x size, so make the pistons to suit! there are notable exceptions, I guess.
It's not that they lack power, they don't deliver it in the same way as a servo wave brake. Over the next few rides I'm going to try a few different things, one of which will be swap out shimano levers onto the caliper, and shimano caliper onto the z race levers and see if each end behaves differently to stock. plus look at what impact fitting better hose has. the stock hose is really flexible.
