What is the extent of his control?
A DoF should have full control over everything football related at the club, throughout the age groups.
1 - He should select managers, the owner is the only one who can veto a managerial choice.
It's clear this hasn't been the case. Every choice has been Moshiri/maybe Usmanov
2 - He should oversee the acquisition of players for ALL age groups, paying particular attention to U18/U23/First team.
Signs are this is starting to happen, particularly at U23 level. Let's not forget that for the first year or two we had an academy transfer ban. He's also been quite ruthless with the culling of players who clearly won't make the grade. There is also the alleged closeness between our 'Head of Academy' (what does that even mean if we have a DoF?) and the CEO. Not ideal.
3 - For the first team (The Coach - with a DoF 'Manager' doesn't apply) tells him what he thinks is needed. If the DoF agrees he strengthens that position. The manager has some degree of input when a shortlist is presented, he can even add his own suggestions but he doesn't decide who we buy.
He stated from the off he prefers to invest in players with potential to grow and increase therefore value. That doesn't mean every young player is a hit, but their is more chance of a return than say an Allan or a James. Both terrific players but it's essentially writing off money to try and take a short cut to the top.
4 - Time. If the 3 points above are under his control you can't judge the effectiveness of a DoF for 4 to 6 years.
Brands is in his 4th year but he hasn't had the usual authority a DoF is given because the club/boardroom is disfunctional.