I think the fact that this is probably the only expansion since wrath where there is one giant looming issue instead of several shows progress has been made. Legions biggest problem that I have seen people mention is the endless RNG it has. Aside from that I believe a lot of people are happy. Legion just needs the next 2 patches to push itself away from the RNG train it's on and I think it will be remembered as one of the greatest WoW content patches ever