For me, it doesn't "fix" the game so much as it gives me all the tools I need to make the game what I want it to be. To really "fix" the game CGL would need to rewrite the core book properly, incorporating all the FAQ info, and some assorted errata/improvements from other books. Instead, I would instead say "with all the current resources, its in the best state it has been in yet, and currently very workable for the GM who doesn't mind the extra work". If I were called upon to run it tomorrow, I could make a go of it using the Seattle version of the Core Book, the FAQ, and the 6WC. I still see stuff in the Matrix areas that makes my head spin from all the if/then situations the FAQ discusses, but most of them probably wouldn't come up with my group. I'm hoping the Matrix book provides some simplification and variant options like we saw 6WC and Double Clutch offer. That would leave us with improvements in all the pillars of the game.
As to ongoing quality, the rules changes seem to be products of a very dedicated errata team. The editing on the book is actually really strong, which suggests people have really been working to address concerns on typos etc. proactively. In fact, I haven't found a single editing issue yet, which is very encouraging. I would hope this represents a higher commitment to quality overall, but only time will tell. If the Matrix book is as strong as this one, the game will be doing even better yet. GMs will still have to go through all the books and the FAQ to make it really play smoothly for their table. Maybe after the Matrix book comes out, someone can do a "Master Edition" that puts all the best/final rules in one place, not unlike the 4e Anniversary edition. That would be a nice thing to do for the GMs and players both.
Hope that helps?