1) Процитирую автора:
"The reasons for this are multiple, not in the least it will allow Pale Moon to implement things that have been on the "to-do" list for a while but which have been pushed back because of lack of time "keeping up" with the (too) fast releases of new versions by Mozilla. The rapid releases often little more than maintenance updates and one or two new features (sometimes even just partially implemented), but requiring a full development/testing cycle for Pale Moon because of the lumped-together patches. Another reason is that from this point on, Firefox will receive a few user interface overhauls to go off on the "Web OS"/"Metro"/"Desktop integration" tangent that goes against Pale Moon's goals of being and remaining a web browser."

2) Воспринимай PM как отдельный продукт, а не как простой билд - будет проще.

Лично я в Palemoon 11 получил все критичные фичи, а появления некритичных могу подождать лишний месяцок - чай, не свободную кабинку в туалете жду.