That may be so, but Blizzard games are always massive hits. If they did a wow sequel it would be huge. But they don't really need too. Blizzard doesn't release a huge amount of games and their sales whilst massive in the first week have very good legs. Which is pretty much the opposite of Dragon Quest is in Japan.
EDIT furthermore their only RPG series that has multiple installments is Diablo, which has increased in sales so far.







