That character has been so mistreated over the years, I would almost think John Byrne created him.

When I was a kid, the (then) short history the characters and teams had carried a certain amount of heft. To me, in that era, it was strangely magical whenever J'Onn reappeared. He was a founding member of the League who had gone off to be with his fellows Martians on Mars II... Time had passed. His story, by and large, was over, which sent a basic message through the rest of the comics, that the authors were going to play fair with the audience. Stories have beginnings, middles, and endings. By allowing certain characters to reach their's, DC suggested the others someday would as well... You gained the sense that you were reading something of consequence and not just this month's useless stack of pages to throw into the mouths of the Deadline Langoliers hot on your heels, as they would be forever and always... 

If some stories were allowed to end, to have a sense of meaning and consequence, then this month's might as well. Or next month's. It felt more exciting this way. 

Bringing J'Onn back for the Detroit Era of all things felt pointless and hollow, like the idea of filling repopulating a Kandorian facsimile with tiny aliens Superman would have to "cure" in a completely different manner than he did last time... Nothing ever ends. It's all just more of the same, forever and always. And by adding Oreo jokes, you make the whole, empty exercise irritatingly self-aware at the same time... Phooey.