The 752s moved the the chashcow centre we know as MAN and then the other went to LBA. Jet2 are positioning 3 738s at NCL so it's not as if we are hard done by, infect it's probably th same amount of seats.
The 757s are getting old, and it pains me to say but they are on the way out. Basing most of them at 2 bases increases reliability for the ageing fleet.