Hi,
I would like to ask any interested parties to test my patch, which reduces the memory requirements of a PO file import by 3MB (given that you deal with a typical complete translation file for Drupal core). This should be a major improvement for those on shared hosts, so that the memory requirement is not lifted because of the locale import.
If testers are found and this is deemed working well, the patch will get into 4.7.0.
Gabor