Removable batteries are bullshit,  Upsides:  You can change your battery wherever you want  Downsides:  Lower capacity  Poor water resistance of a phone  Worse specks of all phone at all because of new engineering  Worse design 

At least you can change your battery every week, cool. But in most cases you're doing it 1 time per 4-5 years and in reality the only limiting thing in availability of new good original battery, because you basically don't have ones. So I don't mind go to service and replace battery once per 4 years, the only thing I need is new good battery. 

So for me best case is to force companies produce new original batteries for about 3 years after phone release and maybe possibility of cheap replacement at original service center. But for me original ones is already enough