Mason was as bad as it gets. Poch was new and was trying to get brownie points for playing the 'youfs' and 'one of our owns'.That pair of Mason and Bentaleb could easily be our weakest midfield 2 among those seasons.
Poch eventually turned Dembele to a real Beast in 15/16. I remembered Poch played him at right midfield may be in the first match against MANU. Then somehow he started playing Dembele in the CAM position while Alli was playing in the CM of the double pivot.