I have also not beaten any of those races you mention, but conversely have beaten ISA, EA, Narn, vree, and despite loosing to Abbai, did so much damage their campaign was effectively over.
The difficulty is knowing your enemy. All Drakh ships are good at one thing or another. Raiders are excelent at maneuvreability and having dodge is great, but they only have 8" range, meaning a death sentence against NOva's, octirions, primus, Most Narn, but then the light raider is an excelent ship against whitestars. destroyers and light cruisrs are great with a bit of range, although the destroyer suffers from forward only firepower. IN a 5 point raid, I myself ususally go for 3 light cruisers and 4 raiders covering both bases of range, and maneuvreability.
set up your cruisrs together to act as your anvil, and your raiders speed and maneuvreability as the hammer and get the enemy in between. Of course this has little to no chance of working against some fleets, but against everyone you mentioned, you should be ok. Possibly drop a raider for a scout when facing the boneheads