Usually it's a very bad sign when a company turns after the marked instead of being a leader. It's a sign of growing too big and getting conservative. It's a steady decline that is difficult to get out of.
Overwatch is a completely new franchise though, so in that regard its novel.
The cashing in can be seen in different ways. Selling out their Diablo IP to NetEase for a mobile game (and having the guts to market it for a PC crowd). Their microtransactions in WoW while still having the subscription model as well. Them laying off nearly a thousand people while profit is at all-time high, while CEO gets bonus. All the silly DLCs for SC2. At least they didn't bother with another DLC for Diablo 3 after RoS.
Mike Morheime left for Dreamhaven together with a crowd of entrepreneurs and daredevils. Hopefully he succeeds where Schaefer brothers failed.
Their early games was not made on the sole reason to emulate something popular.
That was only 2016...
Plus, WoW was released 16 years ago? And their most recent - Overwatch - almost 5 years ago now.