The Ferangi don't bother me as much. They clearly established that the Ferangi were well known to the Federation in the early days of TNG.
Not really 'well known'.
From Picard's log entry at the beginning of "The Last Outpost": ...providing us with the long awaited opportunity to make close contact with a Ferengi vessel.
Starfleet knew of the Ferengi through rumours and reports from other species but hadn't had any direct contact with them, their ships were unknown and the E-D crew had obviously never seen any image of the Ferengi before.