Whats wrong with more diablo likes although I can already see the angry Total biscuit review now "I will now talk about inquisitor and the problem with Diablo-likes for 40 minutes"
Nothing's wrong with the genre, just they don't tend to do very well in general. Especially while Blizzard is still actively supporting Diablo III. Also, a few other reasons for this one in particular, like the Warhammer license being fairly cursed. There's only been two games made in the universe that have performed well and been a success with critics and fans: Total War Warhammer, and the first Dawn of War. Both of which have been in a genre that naturally lends itself to the franchise. Then there's the Early Access stigma. People have been burned WAY too many times on EA, and even when they haven't and the game actually releases, all of the people who would have bought it at release already have it, so sales post-release after an early access development cycle are in the toilet.
And the rumor that Warcraft was originally going to be Warhammer, and they had to cobble together a plot after the license deal broke. So yeah, I can definitely see Warhammer as a cursed IP. And yeah, early access brings more problems than it's worth. The free EA period ending was what caused RagnarokOnline to suffer the hack attack that nearly destroyed it as a game- because a couple of black hat hackers couldn't stand the idea of Gravity making it pay to play. By extension, however, a lot of people left RO for WOW during WOW's EA period... only to reach Level 50 and then come back to RO because they felt WOW was a flop and not grind-ey enough.
WOW never had an early access. It had the standard rounds of beta testing: internal alpha, friends & family alpha, multiple closed beta rounds, guild invite closed beta round*, closed/invitational beta, then public server stress testing. Each round of beta built on the round previous, so even though they were separate betas, the same folks from the one before were the ones invited back, plus a couple hundred more (give or take) from each round. Or thousands in the case of the stress test weekends. * Blizzard decided to send out invitations to leading guilds from competitors games during one of their closed beta rounds, which was unheard of at the time.
