Thirdly, in a diamond your two wider central midfielders - in your case Henderson and Coutinho are the work horses of the side. Not only do they need to function as central midfielders up and down the pitch, they also need to shuttle between centre and wide in order to protect the full backs. In a diamond you're essentially playing a 7-3 system. 7 structured players and 3 fluid attackers. The likes of Milner, Henderson, and Allen are perfect for these shuttling mid roles. I wouldn't want to take our most creative player and make him a workhorse who needs to be disciplined. If we played a diomand despite all it's flaws - Coutinho needs to be number 10.