While used less often now, a lot of old maps have the area marked quite prominently. The Aro Valley War Memorial also includes names from the Mitchelltown area as well. 

Can be seen in an old land and survey map here:
https://ndhadeliver.natlib.govt.nz/delivery/DeliveryManagerServlet?dps_pid=IE18336546

As a result, I would say it is worth keeping for the sake of consistency
