I feel X-Wings got left behind as the Pilot Skill race moved forward and the preference for maneuverable ships became the norm. X-Wings are fine as long as other ships around them are not moving post the revealed dial. Boost and Barrel Roll are what keep the X-Wing from getting into the fight.
Eh, I don't know. In wave 3 it was already getting phased out in favor of the B-wing, and that is not all just because the B-wing has barrel roll. (Although that is very nice.) Even if the X-wing had boost and barrel roll the Rookie would still only be as cost effective as an Alpha Squadron Pilot, and we all know how that has turned out, unfortunately. The X-wing as per the lore is not as maneuverable as the TIE Fighter and certainly not the TIE Interceptor, so I am OK with it not coming with barrel roll or boost stock. In that aspect I think the developers "got it" thematically. The problem is that it just does not have enough bang for the buck. It needs at least a free hull upgrade across the board. That makes it basically as durable as a B-wing, but it costs almost the same with less "frills" (system slot and barrel roll), so it needs to earn its value back somewhere to be viable.