That's why I like to say that to start playing competitively, a player should expect to pay around 150/200$. It should give him enough to explore and find his playstyle, then expend accordingly.
I'd agree with that, perhaps even more. But the thing is, for the minimum cost to play Imperial Assault you can buy a fair amount of X-Wing. I'm not saying IA isn't worth it, just pointing out a flaw in the OP system.
What is hurting the game is the map rotation.
Yeah, and I think you do get a lot of potential value from you buy, but less value if you either don't play the campaign or someone in the group already owns those boxes. In the example of the guy who started this weekend... He has no use for the campaign stuff so he's paying for stuff he doesn't really want.
The stormtrooper thing is another problem. If you don't play Imperials why would you even want that pack? Even if you play Imperials do you need a 4th set of Stormtroopers? Yet FFG is forcing you to buy things you may not want, in some cases for the sake of a few bits of cardboard. It's bad enough that you have to buy the Raider to get the X1 title for the Advanced in X-Wing, but in Imperial Assaults case they're saying you need to buy the Scyk, and the Raider just to play the game, even if you don't use the actual ships.