I suppose the use of Fleet assets does play a major role. Call in lots and lots of support from mighty ships that you paid for with fleet credits. That, and fleet weapons which greatly increase your DPS.
Of course, without team work and lots if freighter healing (constantly dropping tatctical team, transfer shield strength, strengthen shields, Hazard emitters, aux to SIF at the freighter and destroying attackers when these abilities are on cooldown, that won't work either.
Anyone got any strategies to beat the no-win? I would very much like to know.
Although strategy and the right bridge officer setup/captain classes per player and the teamwork for all the 5 players is very important, it is just as much important for all 5 of the players to be perfect players which have their skill tree set-up properly, and know how to time everything right and know how to heal/tank properly.
I'm pretty sure there are several viable strategies to make it to wave 10 and finishing it.
Since NWS enemy choice is randomized, I imagine the enemy factors in as well. Fighting Borg might be easier if all your people happen to have just come off an Elite STF with all their best Borg-killing gear equipped.