This was my second 626; the first had 200K when I sold it to buy this one. It now has 140K. Its weight to thrust ratio is great (4 cylinder 5 speed), so it makes my wife's Protege 5 feel like a dog. Sure, it's starting to make noises and doesn't ride as nice, but it's paid for and gives me 30 mpg in the city. I'm driving this thing until the wheels fall off.
Performance, fuel mileage, comfort, my rotating vents still work.
What improvements can be made, they don't make these things anymore. However, Mazda should remember to keep their vehicles light for better performance and mileage. Remember that folks - an economy car that weighs 3,000 pounds isn't that good.