Expanding out to mobile is not really an issue, the issue with the whole diablo thing is just how tone deaf they are to their community. And this really only came into light because if how tone deaf they are with wow or the fact they have done nothing new of significance with the Starcraft universe in years, it just compounded on it.
I fully expect them to do stuff with mobile, they would be stupid not to, just maybe not forget about your core games and the market that made you. They have benefited a lot from brand loyalty, so yes a sense of entitlement will come of that.