Why do people still use the argument, "If you can't draw, don't complain about other people's art." If a black belt made fun of someone new to Karate for being bad at it they'd be called egotistical or their abilities got the better of them. Being skilled doesn't mean it's fine to be mean either.
There, however, is a good reason to complain since there doesn't seem to be any announcement or reason to change the artist so people can only assume they hired an inexperienced artist to save money like a lot of Chinese manhuas do. (Hire a good artist for a few chapters and then hire an inexperienced one for less.) If, they announced the previous artist had health problems or something of the like no one would complain but no there's none of that and the second season people were anticipating for a long time starts off like this. If there actually is an announcement then I'm willing to be wrong.