Yeah, that's kind of what I was thinking, not the kind of foes who conquer worlds and always-wanted-to-meet-Kirk-in-battle types. Something a little different, something scary or abhorrent, not outright menacing.
When I last rewatched the first season I got the feeling that they may have been trying to pose the Ferengi as a kind of parody of the Federation, or at least, a political group of comparable strength but opposing morals on many grounds. For example, in (I think) The Last Outpost there's talk of how the Ferengi are offended that the Federation's non-interference directive makes them destroy perfectly good trading opportunities; or how the Federation's insistence on gender equality makes them degrade women by putting them in clothes and such. (The latter's almost as silly as the former is respectable, but it's at least a motive that isn't mostly just Roddenberry waiting for the invention of DeviantArt.)
If they were going for that --- and the first season I think they were trying for a lot of subtle concepts they weren't really able to pull off, eg, the original conception of Data as being as human as possible without being human, the sort of thing you could build a great philosophy course around --- then I'm sorry they weren't able to pull it off. A Federation rival power that could be as smart and generally respectable as the Federation but different from it, would have expanded the scope of the Trek universe in ways it really hasn't properly had.