The best use for the Firespray that I can fanthom is to use it as a deadicated missile boat. Take Trelix (secondary weapon reroll) with the Slave 1 upgrade then load it with a proton torpedio, cluster missile, and seimic charge. Use the torpedio the first time you can target lock, then the the missile in the proceding turn (assuming you can get your movements right without losing your action in a colission). The first turn you can clear the parking lot you drop the charge as you move past your opponent's ships. From there out you just need to keep the enemy in a fire arc and keep the main guns pounding away at them.
The one new card that I have problems with it the Proximity Mine. The biggest issue I have with this is that it requires an action to put it in play. This generally means that your oppenent is going to have time to avoid it or just got really unlucky in the movement selection. Most of the time they will just be able to avoid it. Since the most that can be in play, at this time, will be 2, I don't think proximity mines will have any decent play value until the Tie Bomber comes out. At that point it may be possible to take enough mines that you can choke the board with them. MInes will be something to revisit when the Tie Bomber is released.
I think a new combo to consider in the expansion will be Lando, Gaven, and Dutch. With the right upgrade cards and play style it should be possible for each ship to get 2 actions a turn.
I totally disagree with the Firespray, you should be using it for the heavy laser or ion cannons most of the time, leave the missiles to the TIEadvs. I can tell you that it is simply horrid as a ship, and unlikely to be something you will want to bring to a tournament, due to multiple problems plaguing it. As for the proximity mine, you could try ramming your firespray in straightaway, then have someone else come in and squad leader it to drop the mine, after you have "aimed" the mine and know for sure who will hit it etc. Either way, you really do not want to load it up with multiple missiles/torps, because you will have very little chances at firing them off before you die. If you already think it is hard to do that on the Ywing, it is even harder on the Firespray.
come wave 2, PTL will be the most played upgrade I guess, and this will also mean that we will see less of wave 1 stuff like squad leader and expert handling for instance. Marksmanship has a little bit more reason to be played now, and so does maaaaaaaaarek, but otherwise PTL and maybe elusiveness should be the most played upgrade. we might see less swarm tactic chaining as well, as less ships are fielded and the pilot skill points are generally increasing across the board. Old rebel builds like 4 Xwings etc will still see some play even with the enw ships, abeit with some minor tweaks to incoporate new wave 2 stuff, but for the imperial side, the widespread spamming of stealth device would most likely mean the old 7-8 TIE/ln swarm will not be seeing much play anymore. instead we would be seeing a lot more TIE/in, with the numbers generally around 4-6 ships for any solid imperial build. The game will be a lot faster and merciless too, with the general improvement in the quality of the attacks. one bad range 1 exchange with all blanks on your evade rolls would pretty much guarantee your ship is dead, unless its hp is comparable to a Ywing, and with lesser ships being fielded on both sides, that would be very painful.
Predictions about the assault missiles missed the mark entirely. i tried against my 8 TIE swarm throwing 4 assault missiles at it with 4 TIEadv (yes, points are unbalanced, i know, it was for testing), and it dodged 2, ate 2 assault missile with each missile getting about 4-5 ships each in total, with about 3 ships that took both assault missiles. Then afterwards the 4 TIEadv just straight up and got chewed apart by the 8 TIEs, of which at the end of the game about 3 were left, but still it proves the point that the assault missile isn't as damaging to the swarm as claimed. You could really easily eat 1 to all 8 ships and treat it as if the missile didn't even existed, although 2 is rather painful, but nowhere near fatal. not even close.
closing note: i feel PTL should cost 4 points and sexpose should cost 3 points