The season has just started, but I've seen enough of Arbeloa. It is clear Fulham need a different manager - soon. Under normal circumstances it is reasonable to say "give the new guy some time, three matches isn't enough to make a judgement" but Arbeloa is not acting in a way that deserves that leniency. My concerns are:

• The formation - the most charitable outlook on what we've seen so far is "Let's see if he can adapt this system. If he can't change then we should let him go." But my question is why would any competent manager attempt to play this way in the first place? It was obvious where the gaps were to every single person watching these matches. Even if there were some kind of players out there that could make this system work, they aren't playing for Fulham. That fact that Arbeloa even attempted to move the wing backs so far forward and split the CBs with this squad shows disturbing naivete. 
• The substitutions - At least the subs haven't come late, but many of the substitutions have been head-scratchers. Rather than improving Fulham's chances later in a match they've made the team less effective. Arbeloa has shown himself incapable of reading the match and seeing what is needed.
• The locker room - When we saw the poisonous environment at Real Madrid, we all gave Arbeloa a pass. There were things going on there that preceded him. However, he didn't fix it either, and based on player reactions we've seen so far, he doesn't seem to understand the men he is working with. I think Silva's best quality was his ability to get almost every guy on the squad to feel part of the team even if they were spending most of their time on the bench. Arbeloa just doesn't have that.

There is enough evidence to say Arbeloa isn't ready for this level of competition. The only thing he has brought is some football that is exciting to watch at times, but that is only because of the general chaos of his approach. The longer he stays, the more likely Fulham will be relegated.