Originally Posted by
styil
WoD started with over 10 million subscribers, and after the expansion's performance, this number collapsed to about 5 million and lower.
The remaining few million players are mostly passionate veterans of WoW, and because of this passion, any change is magnified. So they see 1 extra patch from WoD as extraordinary. Only problem is that these are mostly the only players remaining, so there is a bias towards threads portraying Legion being a good expansion, despite millions of dissatisfied players leaving in the last year or two who are not voicing their opinions since they are no longer around.
In summary, most of the remaining players are irrationally optimistic about the game which leads to a positive bias towards the quality of Legion.