I tried to balance this map for PvP play
https://raw.githubusercontent.com/andy5995/0ad-maps/trunk/maps/skirmishes/Cliffs_of_Carnage_4v4_8p.xml
https://raw.githubusercontent.com/andy5995/0ad-maps/trunk/maps/skirmishes/Cliffs_of_Carnage_4v4_8p.pmp
The concept is nice, problem is 0ad has issues with bottlenecks, too easy to turtle depending on the civ especially.
I think removing the bottlenecks and keeping the elevation, which already gives some defenders advantage could improve the map.
I checked the listed bugs based on the above and with my limited knowledge of 0ad development I see the following.
Mac display and keylogger issue can be fixed by simply updating sdl which is a nobrainer and a must do anyway. The only question if users of old mac os need to build from source on their own or whether to provide some ld_preload equivalent wrapper so one package can suffice or whether to provide two separate packages.
For BSD there are couple of patches probably by the maintainer of the 0ad port. The trivial bits should be merged and stuff you aren't sure about without some research can remain part of the port for now.
As for Linux the only obvious issue is the dependency on python2 which is against packaging policy due to it being EOL. From a quick glance python is only used for unit tests and maintenance tools as in server side components. So basically it's just dependency for running the tests and as such can be overlooked by a packager short term.
The Ryzen issue seems understood and patches are available even if you have to call them hacks.
Most importantly none of them are regressions. A broken a24 is still better than a broken a23. The most glaring issue of all is no release in 2 years and not the quality thereof.
@mysticjim I'd been looking for that same feature (Population Count) for a long time with no luck, so I created my own mod for it. Check it out and let me know what you think!