Again, there isn't a single expandable game where every printing remains viable throughout the game's lifespan. The fact that as much of the old stuff is still playable after ten waves is a testament to good design, not bad. I think you have very unrealistic expectations.
However, Corvus Belli was smart and they did not paint themselves into a corner by using cards. Instead, they just revised the unit stats PDF when needed and with the introduction of 3rd edition they went even further and now the official source for up to date units stats and costs is the online army builder maintained by CB.
The main problem with any changes in X-Wing are the cards. Any dramatic changes would require FFG to release a big card pack with an update of everything. Doable, but not easy and certainly not free. What they could do is release a PDF with corrected card images, so people could print them and sleeve them with the cards they have, while at the same time packing the updated cards with every new reprint (marking the cards with a symbol indicatng a revision). This way the old cards would be slowly phased out.