Honestly, it's kinda selling Okouchi's resume a bit short. While there's duds like Valvrave in there, he has a long history in the mecha genre - Turn A Gundam, King Gainer, RahXephon, Eureka Seven, Code Geass, Comet Lucifer, and Witch from Mercury. Even the non-mecha stuff can be fairly notable, like Devilman Crybaby or Lupin III: Part 5. The biggest thing I suspect and would hope for is that he'd be someone to treat Grendizer with in-universe significance and symbolic weight - whether going with the 'the Vegans bult it as the ultimate vehicle of their conquest' or the 'it's actually Planet Fleed's ultimate weapon, built in the image of their war god' origins.
Fukuda has similarly been in the genre a long time - going back to Dragonar, of all series. Though most (in)famous for his work with Gundam SEED, and more recently Cross Ange, the man has done Exkaiser, Da-Garn, Wataru, Granzort, and Gear Fighter Dendoh - the latter of which honestly may take a lot of inspiration from Grendizer in the first place
Along with Tanaka Kouhei, and this might well end up feeling like a turn of the century Super Robot show made in the 2020s, and if they pull it off, I'd be here for it