I've just finished a solo run through (2 ships) while limiting myself to the X- and Y-wing only. I found that the X-wing is great at mid-campaign, the Y-wing is great early campaign, but neither are particularly good on the later missions. I had enormous trouble with "Revenge" where I was out-Pilot-Skilled and outmaneuvered. Only a well-timed bump saved me. It got me thinking about the other difficult missions - Capture Officer and Disable Sensor Net chief among them. What makes them so hard?
For Revenge is was the extremely focused, high-PS enemy Interceptors, plus the terrible losing condition.
For Disable Sensor Net, t was the waves upon waves of Interceptors that come in during the mid-game. I can't imagine playing with 6 players in such a minefield.
For Capture Officer, I think the main problem is attempting it with early-campaign ships. X-wings and Y-wings just don't have the punch to get through that Jammer + Flight Instructor + Protect Action defense in time. The only exception is when you bring a Y-wing with 2 proton bombs, where disabling happens very, very easily.
What missions did you find hardest, and why?