Outsourcing has nothing to do with it.
Even if they outsourced it (which i doubt), then that's down to art direction given to the contractor.
Same shit happened with Reforged, they conciously chose a shitty artstyle, told Lemonsky Studios "this is what we want" and Lemonsky delivered that shitty artstyle.
Outsourcing is generally not a bad thing, you just have to give these people proper directions and instructions of what you want.
If your directions and instructions basically describe excrements, they will deliver you shit.
That the modern artstyle deviates from the original one isn't something that people are just discovering now.