why should he tho? this game has an open world, it heavily supports multiplay (infact kind of even needs it when we are talking about world bosses legion events etc)
I mean i do know some people would love d4 to be a solo player game, with its ssf mode… eventually moddable? But it isnt, and for the foreseeable future it wont be i guess.
id say the people who knew what they were purchasing can be happy that things become “slighty” more difficult. (lets be fair, its still going to be easy)