I just watched Ideon: Be Invoked, the movie conclusion to Space Runaway Ideon, the super robot anime that Yoshiyuki Tomino made in 1980-82, immediately after his original Gundam series. I'm stunned, frankly. I knew that the show--and especially the movie--had a reputation for being grim, but I was startled by both the matter-of-fact way it handled its violence and just how resonant Tomino managed to make his themes of war's self-defeating futility in a show ostensibly about three oversized trucks that combine into a big red robot.
In some ways, you could consider Ideon an anti-super robot show. Unlike grounded, 'real world' mecha shows like the Universal Century Gundam series, Patlabor, or Votoms, the popular image of super robots is as straightforward power fantasies for 10-year-olds. Ideon appears to start out this way, only to turn it on its head by the end. The story increasingly becomes more reminiscent of Urotsukidoji's apocalyptic visions (thankfully without the tentacles) than something like Tetsujin No.28.
And yet, it's far from the only super robot show to do this, almost to the extent that the anti-super robot has become the true super robot. Evangelion, RahXephon, Gurren Lagann, Getter Robo Armageddon: they all start out with action-figure-friendly robots punching each other, and culminate in metaphorical or literal rituals that reshape life as we know it. Then you have something like the 90s Giant Robo, which both revels in and subverts classic super robot tropes.
I'm curious to know which other super robot anime have gone down a route like this, which you thought handled their deeper themes most effectively, and especially where the trend started. I'd guess something from Go Nagai in the 70s was the first, but I haven't seen much anime from that period, so I don't know what. Any thoughts?