Of course Wayland will have bugs. What it won't have (hopefully) is the same design decisions and flaws that X made, because people have learned from X in the intervening decades since its inception.
That doesn't mean that it's not a net-positive to develop and start using it, of course.
Maybe they were great at the time. If you don't have enough memory to store every pixel of your screen, only storing properties of some basic geometric shapes seems to be a nice solution. If you have plenty of memory and want to control every pixel this becomes rather useless and even a burden.