Even with the same make up and costumes, the Ferengi could have been written as maniacal and menacing. An early decision by TPTB could have been made to have the Ferengi win on occasion, this would have made them a more credible enemy. The Borg were diminished by their constant defeats at the hands of the Voyager crew.
Basically have them be the Orion Syndicate, the Orions have become puppets within their own organization..
Largely remove all aspects of humor and goofiness.
Make them less "Yankee Trader" (who there was nothing wrong with) and more the British East Indian Trading Company.
Get rid of "The Grand Naggus."
None of these suggestions would have precluded Ferengi like Quark and Nog being part of the mix.