We’ve known that crew survivability can be enhanced by isolating crew from the ammo, and providing blow-out panels to direct any cook-offs away from the crew. These features are usually designed in from the beginning, as in the M1 Abrams or T-14. Let’s look at a test bed designed to add these features after the fact.
The M2 Bradley Fighting Vehicle and M3 Cavalry Fighting Vehicle carry an awful lot of ammunition, and aren’t super well protected. US Army studies indicated that an infantry carrier like the Bradley was likely to be targeted by anything on the battlefield, including the antitank weapons that it really wasn’t designed to resist. While explosive reactive armor could be added to supplement existing armor, this wouldn’t do very much against APFSDS rounds.
The Bradley Advanced Survivability Test Bed (ASTB) implemented a pretty extensive redesign of stowage. Most of the TOW missiles were moved to hull stowage racks outside of the crew compartment, with three missiles in an external compartment in addition to the two in the launcher. Two more were stored low on the floor of the crew compartment, although these could be replaced with Dragon missiles that were of more use to the dismounts. This limited amount of stowage in the crew compartment was intended to allow the vehicle to fight if the external stowage was not immediately accessible. Reserve 25mm ammunition was compartmentalized, with blow-off panels and separation for the rounds provided in the compartments. As a result, reserve ammunition capacity was reduced from 600 rounds in a regular M2 to 588 rounds in the ASTB.
Fuel was also mostly moved to large, external tanks at the back of the vehicle to prevent fires in the crew compartment. A 30 gallon “get home” reserve tank was provided internally.
The ASTB was also fitted with spall liners, additional applique armor, and protection for the sights. These features would get rolled into production models of the Bradley after live-fire testing of several models, including the ASTB, in 1987.
As for the rest of the features, I do not know why more were not adopted.