bearophile can say "i told you so" (re uint->int implicit conv)

[Kagamin]

I'm afraid, a factor of 2 is too small. If an application needs 
gigabytes, you'll have hard time trying to convince it to not use 
more than 4 gigs. Or more specifically between 2 and 4 gigs.

Your examples don't specify if those applications needed large 
contiguous allocations (which is another problem in itself), only 
a memory consumption. Actually a program can consume more memory 
in small allocations, because this way it can use fragmented 
address space to the fullest.