Having finished Star Trek: TNG, I've moved on to DS9, my favorite Star Trek series.
I like how the series was willing to make retcons in order to better serve the story. DS9 made Ferengi far more interesting than TNG ever managed to, but I have to wonder what might have happened if Ferengi had been approached differently from the start, and never relegated to the role of comic relief snake oil salesmen.
TNG tried to introduce them as a new warrior race to replace the Klingons as a violent threat to the Federation, but that whole angle fell completely flat. I realize it could never have happened this way at the time, but what if the Ferengi had been competent businessmen from the start. They could have been the only thing more terrifying than space-warriors... They could have been space-capitalists. The Dominion, only instead of having enslaved other races, they had made them financially-beholden. A military-industrial-prison complex led by rich businessmen who sound very reasonable on the surface. Trading in not just technology and goods, but culture and entertainment. Have them spread disinformation that makes the border colonies question if the Federation has their best interests at heart.
Honestly, I find the idea terrifying. Probably because a realistic future might end up with humans being that civilization to a space Federation we meet.