most game deviate slightly from their theme when you go into min maxing for tournaments.
But personally I prefer this because otherwise you almost have to enforce too much order, which limits creativity and free choice drastically.
Besides, tournaments are probably more about balanced mechanics than theme, while scenarios and casual sessions allow more room also to play thematically fitting unbalanced force mixes etc.
tournaments are more abstract anyhow with allowing IMP vs IMP and rebels vs rebels - something I would try to avoid hard in casual play (not that hard if you provide both sides for a casual game, then this is the natural distribution)
...X-wing neither needs nor wants a force organisation. 40k does, because it's been designed into the game from it's basic level - as noted, a 'special character' is fundamentally different to a line squad member, and can be made nigh invulnerable for relatively little effort. By comparison, just last night we saw a named Interceptor ace successfully roll 4 blanks on his evade dice and explode in a single volley of fire, shield upgrade and all...
...
Soontir Fel has a reputation for rolling green blanks - at least when I play him. ![]()