I was thinking about this last night but not to the same degree...i.e. more subtle.
for example
Beyond a certain rank one should get
1 extra smoke for Squad leaders. (but only two can be live at any one time, as it currently is)
Extra clip of pistol ammo for SL/s or other kits with pistols.
1 extra mine for Engineers. (but only on larger/african maps. 5 isnt enough on sidi rezgh for e.g, desert maps have less statics overall and placing mines seems always like a waste of time. It is hardly rewarding waiting a 40mins only for a tank to drive thru your minefield because your 5 mines are 10 in-game meters apart.)
Binocs for AT. (perhaps with ability to place arty markers removed).
Small things that only add a little bit more weight to a ww2 typical loadout.
While this would make 'deployed' loadouts not exactly historically accurate, whats not to say a hypothetical soldier would not make use of things found on the field? Soldiers would definately grab a pair of binocs from an enemy combatant in ww2, it's not unrealistic. A nice touch would be make the binocs at spawn, that of the opposing team.