I'm not sure what your questions is- You want to know the value of stamina, right?
I think stamina works as a modifier to the other skills, so when players have low stamina their skills are reduced, especially as their minutes played go up. SO, in the 4th quarter you might see subs in the game instead of starters or you might see players playing worse.
I know very little about the GE but I do know that in real life being in good condition and shooting free throws well are two of the most basic keys to being a successful basketball player. So, for me, it makes sense to have those kinds of players on my BB team. In the context of BB if you have high stamina then you can play fast-paced tactics and not suffer at the end of the game.
I don't really play the market much, and I don't do it well at all, so I'm the wrong person to ask. I assume that other skills being equal, a player wiith high FT and Stamina will sell for more than one without.
Also, I don't think it is that improtant for the majority of players in the game who are following some sort of accepted formula for being successful. I don't really care to do it that way, even though it means my team isn't that good. Like I said, I am lucky to be in a small country where you don't have to follow one road to success.
Once I scored a basket that still makes me laugh.