I think most of what Gotham has going for it is that the city is almost a character all on it's own. Even without Batman it's still an interesting, colourful and bonkers place in which to tell almost any story.
I don't know that Krypton can have that same appeal. I mean the society of Krypton has always been about the least interesting part of Superman's backstory, in any iteration. It's all hyper-advanced technology, stuffy councillors and an entrenched, stagnant culture. Not really an enticing backdrop in and of itself.
Perhaps going back a couple of generations will given the a bit more leeway in that could explore factors that perhaps lead to Krypton being the stuffy buttoned-up culture that's generally portrayed - perhaps even looking events that would later result in Jor-El's warnings about of impending demise.