For those that currently or in the past have owned a Phantom 4 (either Pro or Advanced) would you consider the MA2 to be an upgrade?

It depends on what you want a drone for. If it is for aerial photography, then the P4 is hands down the better camera with a 1" sensor, as against the MA2's 1/2" sensor, which is nothing but a jumped up phone camera sensor.

Its certainly more portable but the P4 camera has a "look" that a lot of people like.

Upgrade over the P3 yes over the P4 no. the MA2 only advantage over the
P4 is portability.