This was originally requested in
http://octeth.com/forum/showthread.p...-the-interface

and was partially addressed in the new 4.3.4 update:
[OEMPRO-1517] - Order the custom fields in ASC order by their IDs in subscriber form import screen

What is required is a new database field to store a 'sort order' or 'weight' of each field. Then, in the administration screen, all we need to do is define a number for each field to define in what order they are displayed.

If multiple fields are given the same weight value, then sort alphabetically.

A simple adjustment, really, and improves the subscriber experience tremendously.