I'm talking about failed prototypes that don't work properly, 'advanced' projects which turned out to have serious shortcomings or were awkward to use
Of all the factions, the Star Army probably has the most of these types of things (if not all of them among SARP's factions).
The
Space Daisy was obsolete when it was made and has long since been discontinued from production (and mostly existed for aesthetic choice).
The
Mindy 3 project was cancelled in favor of the superior Mindy 4.
Then there's the
MCAS, which has never really been widely adopted because both Mindys and Daisys are better in their roles.
The
Himiko-class Light Escort never made it into full production past the first two, with the first model specifically having power management issues. An advanced project that had serious shortcomings.
The
Hayabusa SD variant is stripped down and lacks FTL so it can be operated by planetary defense forces. Literally designed to be cheaper for garrison forces.
A lot of Yamataian power armor accessories were purpose built for specific PA models and then are subsequently provided as a universal "stopgaps" to be used outside of their intended design.
There's
way more, too, but I don't want to spend a whole post linking to every single piece of failed tech. Look at all of the weird
Nekovalkyrja models from over the years (and others not on that list like
NIWS, which was phased out for its operational shortcomings). And on top of technologies that have explicitly been made obsolete, didn't pan out properly, or were never particularly good in the first place, there have been plots based around development that utilized testbed technology like the
LAMIA Kai or the
Serendipity Class. Even great technologies, such as the Thought Armors that came from the LAMIA Kai's lineage, are sometimes underutilized because of misunderstandings on how they're meant to operate (which is a very human-side failing on the part of strategists/tacticians).
Technological development, including failures and half-successes of imperfect inventions, has always been an important part of Yamatai and the Star Army's story if you don't overlook it. It's one of the faction's central themes.