Seems logical. But keep in mind that the more it deviates from classical chess, the wackier the game will look to newcomers. Besides that, 11 is such an ugly number! 
Here is a relevant topic: Reevaluation of piece values
Queens more points?
 
    
  
  
   
    
  
  
  I think queens are rook + KNIGHT + pawn 
The additional value for a bishop is because long range matters a lot more in this variant.
 
     
      
Hi, I was just thinking that if bishops worth 5 points, so Queen maybe 11.
In two player chess:
-Queen = Tower + bishop + 1 = 5 +3 + 1 = 9
In four player chess:
-Queen = Tower + bishop + 1 = 5 + 5 + 1 = 11
What do you think?