My gaming background is in board wargames, I was a teenager back in the heyday of Avalon Hill and SPI, and more recently I've played a lot of GMT or Columbia ar MMP wargames. In a typical board wargame you will get, as well as the main event, a handful of usually smaller scenarios. These specify starting positions and order of battle – a list of exactly which units each side gets to play with – and victory conditons, special rules etc. In a good quality game each scenario will have been carefully playtested to make sure it is more or less balanced, so that given players of equal ability victory will go to either side roughly the same number of times. So for example Up Front, one of the the finest wargames I have ever come across, has a dozen or so scenarios printed on the back page of the rule book. Each one is a little gem of compression, specifying the exact composition of your squad and their weapons, the setup conditions, the kind of terrain you are likely to encounter, and the victory conditions. Each one (remember this was back in the golden age of Avalon Hill when they had big print runs and plenty of resources) was thoroughly polished and playtested, so you could be sure you were getting into a fair fight with your opponent.
Star Wars: X-Wing in contrast went for a points-based build-your-own-squad approach. I can understand why, after all many people thoroughly enjoy the meta-game of squad building, the obsessive poring over lists which can fill the fan's leisure hours (and some of his working hours too!) But the price of this is a certain rock-paper-scissors flavour to one's encounters down at the local club. Your obsessed-over squad is quite likely to meet an opposing squad which simply steamrollers yours, with no possibility of playing skill or luck rescuing what is from the start a hopeless situation.
Interestingly, even Up Front, which I am holding up as a shining example of balanced scenario design, gives every personnel and weapon card a points value, so points-based DIY scenarios are very much possible, and were a lot of fun whenever I tried it, back in the nineties when I was playing a lot of Up Front.
Stll, it would be nice to see FFG produce some proper balanced and playtested scenarios. I think it's unlikely, the current structure of the game with numerous upgrade packs marketed as single (or sometimes pairs of) ships, would make it difficult. The missions are a step in that direction, but you are still choosing your forces on points value, so the meta-game intrudes even here.
