How about applying a Bell's Theorem effect bassed on the Players Aggression... please note that I am not that familiar with the Bell's Theorem... I just want to give the Idea based on what my perception is.. and here it is:
Verry Aggressive Players in really life are highly motivated over their passion and to put effect in-game... that they could store more energy to give compare others with the same Stamina range... especially if he is not Injury Prone...
ANd theres the other side of the Spectrum which is the Very Passive Players... that they are very good at Managing their Energy very well... Probably they choose when to do their action according to the situation to their EXP...
BB can make those players' attributes for Game Shape Calculations too...
that PLayers that are at the end of the spectrum could manage their GS well than the others on the middle of the spectrum...
and PLayers that
played very High minutes on their Developing years should increase their GS drop Resistance on their Prime and or make it natural for them to improve STA over time (Just like EXP does)...
Players that are
not used to play high minutes from their Developing Years that have been forced to play High minutes in their Prime should not have that High GS drop resistance and should have a slight disadvantage against players described above...
and other situations the BB would see fit...
(https://i.stack.imgur.com/Baia6.png)