tl;dr: sometimes the solution to a bad drawing is to practice on something else
Finally, the completed page. Frankly, meh.
I could have done a lot more work on it to clean it up, add some pop, fill in some more cloud layers, etc., etc., but diving into the fiddly bits on this particular composition would not fix the deficiencies in the core drawing or in my abilities to realize it.
The solution, I think, is not to overwork a single piece of artwork trying to compensate for its deficiencies, but to instead identify those deficiencies, to practice to eliminate them on different drawings, and then to return to the original subject matter with a wholly new concept and composition.
In this case, the deficiencies - oh, I don't know where to start. My poor hand drawings, my lack of details about body anatomy, my poor inking skills, my lack of strategies to overcome my slight RSI tremor, my poor page layout, my lack of knowledge about digital coloring techniques, or my need for strategies to overcome my moderate color blindness? But identifying even a few of them starts me on the road.
Note fixing these issues requires a comprehensive approach: some involve practice, like drawing hands or working on inking. Others require research (and practice): learning more anatomy or digital coloring. Others require actual strategies: if I want to clean up my inking line, I need to focus on ways that do not irritate my RSI or trigger the slight wobbly tremor, and if I want to deal with my color blindness, I need both more knowledge of color theory and a plan to deal with it. But now I have GPS directions.
Time to get started. And at some point, when I've traveled around the country of comics and returned to the start with a better set of tools, perhaps I'll draw another Batman cover. Or a Green Lantern page.
Or ... maybe ... a comic of my own design. Not that I have one in mind or anything.
Till then, drawing every day.