meanwhile in fiction the running gag of the Gundam Build series is that there are characters who used the retro kits as in their unmodified state in a Gunpla Battle and won despite the kits lacking modern articulation is probably due to the Battler's sheer skill, one such character is Mr. Ral from Build Fighters probably because he is Mr. Ral, lol.
Im slowly crawling through my Proto-Dom and i've had the same issues as you in parts. Mostly the whole "glue together" part i didnt expect and how little mobility it actually has. I long hesitated to cut the torso at the waist to add some rotation to it as well but decided to keep the proper 80s look to it cause i didnt feel confident i could pull it off cleanly. The Dom has the same ankle joints as well, one of mine of course snapped on assembly because of tolerance clearing so its a bit more wobbly than the other but thankfuly it isnt an issue as the entire kit is a brick. For the skirts, maybe try using PLA tubing to just attach them like a door hinge or if you dont need them to move, straight up glue them on as is.
You could attach the skirt via a spring that went all the way around kinda the wasist like a belt like the pg zaku 2 head pipe section but you attach the skirt armor on the spring sides via tubes on the back of the skirt armor it would work pretty well
There is a manual of HG Winning Fumina where PC-F which is a universal polycap ball joint that can insert any 3mm rod while the ball can be inserted in a joint socket just for reference. Then you get the idea on how to move the Zaku skirt and other movable parts.
Oh I would definitely recommend the MG. You can get the standard version as it’s not a P-Bandai exclusive, but it may be harder to find as it doesn’t get reprinted often
Zeon Officer:The Feds have a Guncannon. Do something Zeon Engineer: Puts cannon on Zaku Zeon Officer: The Feds have a Guntank. Do something Engineer: Puts Zaku upper body on a tank Zeon Officer: The Feds have a Gundam. Do something. Engineer: Puts Zaku head on a dam.
Not gonna be a TON of modifications. But yeah in the future next time I want to try building and painting one without any modifications other than seam removal and basic clean-up. Just to capture the original essence