>>23371006The power fantasy angle is one that usually is not very conducive with mecha.
If you make it an OP robot then there's this feeling that the MC isn't the special one because the robot is potentially carrying him. Yeah, usually a lot of these series have the MC be handed some amazing ability for relatively little effort but that still is something that people who like those series have in mind. It's probably why isekai are usually giving the main character unique "skills" as their core feature instead of overpowered items, even something like Shield Hero where the setup seems to be placing emphasis on the shield it actually is something that still is linked to the OP skillset of being summoned as a special chosen one.
If you try and make it that the robot isn't special then the MC also loses out by not having some unique special ability which is a huge part of the thing the audience wants. Again, if it's something that is simply a matter of one person being extremely competent there's always the threat of someone better coming along. Consider that the largest power fantasy slop in recent history had it downright hard-wired into the setting that ONLY the main character can get stronger despite that making no fucking sense, something that works for the audience is the idea that literally nobody can challenge the self-insert, not even hypothetically.
This might be why so many of them feature the "free cheat skills" because it immediately gives the MC a plot-excuse that marks them as completely untouchable.