Another way to look at it...
Since the game's initial release, there have been 41 box or blister pack releases, including Wave 8. That breaks down as:
2 core sets
3 boxed sets with multiple ships (Imperial Aces, Rebel Aces, Most Wanted)
4 huge ships
9 large ships
23 small ships
The initial core set was released in September 2012. That's 41 months ago.
So there's been essentially one release a month. Far from overwhelming, I'd say. Your mileage may, of course, vary.
It's not the number of releases; it's the permutations that expand at too fast a rate.
It's not just that the K-Wing was released... it's that it included the TLT, Miranda Doni's ability, Asege whoever's ability to give (or not give) focus to a Huge ship, the connor net, SLAM... that's one release.
To say nothing to balance of power.
I'm fine with new releases; it's rules that step on themselves that become problematic.
And power creep, which is perhaps in the eye of the beholder, but a commonly experienced growing pain in a popular game.
What you describe is something that cannot stay static - if the game is static then it is no longer living and complete (ie no more updates and patches). Perhaps you would be more happy with such games rather than this one.
The "complete" package game includes most classic games - Chess, Go, Monopoly, Risk, etc and many new games, including offline PC & video games GTA, Fallout, etc. Any former expndable game that is no longer officially supported with expansions can also be be considered "complete" eg Decipher's SW:TCG, ST:TCG, most of GW's specialty games, etc.
The expanding or living game (the type of game that X-Wing is) is a newer format sells itself on the exact same points you mention as being problematic. All CCGs, TCGs, living card games and expandable miniature games such as Magic:The Gathering, Heroclix, Mage Knight (when they are being supported by new expansions), as do most MMOs such as World of Warcraft, SW: The Old Republic, and many more.
In between the 2 is the continually revised edition games, where a game runs with occasional expansions (similar to an expanding or living game) but gets revised to a new edition every few years (at which point the old edition becomes a "complete" game) - many old wargames and RPGs belong to this group - eg Warhammer, Dungeons and Dragons, Squad Leader as do some MMOs eg Guild Wars, EverQuest.