First of all, thanks for writing the report. I enjoyed reading it, especially because I play both these armies.
I wanted to say, though, that I had a similar experience just recently with a non-standard mission (in this case, the raid mission Ambush), where I felt like my opponent was at such a severe disadvantage from the start that it hurt my enjoyment of the game a bit. He didn't have a very mobile force, and being forced to cram all of his units into a very narrow column, while I got to take nice positions with ideal cover and line of sight, all at a desirable distance from his army (Pathfinders far away and above in cover, Wraithlord pretty close, etc.), was punishing. On the first turn I was able, without any exceptional luck even, to completely cripple his shooting, and it seemed like a bit of a mop-up from there. This is not to praise myself, but to condemn the design of the mission. His army design was not at fault, out of context. It would have been a similarly up-hill fight for me if our positions had been reversed. Also, he made no terrible decisions, IMO, and for myself, I did nothing particularly brilliant. I really shudder to think what would have happened if I had been able to bring ordnance.
Point is, some of these missions just seem tremendously skewed unless each player knows which role they'll be playing and can tool their army for that. Bringing a take-all-comers list, or randomly determining who will be attacker and defender, can lead to games where it feels like the outcome is a foregone conclusion. Not that one player ever literally has no chance to win, but starting a game with a slim chance at victory is not a pleasant experience to say the least, even in non-competitive play.
In short, I wouldn't recommend non-standard missions to anyone unless the roles (attacker and defender) are predetermined and the army lists are specially designed for those roles.
