not even just mathematically sound.
In the movies a single xwing takes out tie after tie after tie. They have vastly superior guns, but in game theyre only +1 die. Had they been +2 it probably would break the game but i dont think having slightly more accurate than normal 3die would be gamebreaking and that would give them that edge over tie fighters.
I've often wondered if they would have more design space if, at the start of the game, they had doubled all of the stats (i.e. TIE Fighters at 4/6/6/0, XWings at 6/4/6/4). That way they would have more room in between ships.
Edited by Audio Weasel