DSA is reliant on seasonal leisure travellers, there is only one route which may appeal to business pax but that is only 6x weekly after failing to bring in results on a 2xdaily service. Suggests to me that business potential is negligable.
STN is reliant one or two based airlines like skipness says, DSA relys one one comparitively small based operation from TOM. Taking both into account i know which one will have a better future, better an airport near London than one near Doncaster dont you think?