It would add to discoverability if a reminder of the bang appeared besides the search results (could be under a config setting), that way one could learn the bangs associated with their most used sites easily.
That's a good suggestion, though DDG has a financial incentive to keep users going through DDG's search page. OTOH, DDG created and supports bang shortcuts so they want people to use them. :)
DDG could show a bang suggestion if any of the top search results are for sites that have bang shortcuts. Or suggest "Didn't find what you're looking for? Try !g" if the number of results found is small.
you get a help text in a tooltip (hover text) with the URL of the search engine - when the mouse hovers over the link; I think that adding the url directly to the table entry might clutter up the page.
