Icing on the default a320 is over done. No icing is accumulated on an jet airliner that way, as the aircraft flies too fast and not too much time spent inside moisture/clouds during icing. The only areas of noticable icing is on the pitot-tubes and other small air frame areas. But not like what we see on the default a320/747 etc.
The icing model is not accurate/realistic on airliners in MSFS.
We could have done it, as it was very simple, but its not realistic.