The problem with this kind of filtering is that your problem isn't getting solve more so that you are reducing the amount of players that can join your PF. Knowing how players think, most will always, always select the highest number option that the developers decide on. For example, let's use "10" times completions. You are going to select "10" times completions because you want "experts". At that given hour that you opened you party finder, only 3 players are on that have "10" completions. The PF timer runs out and you have to re-queue.
Than you have to decide, "Well, I'm going to have to accept a bit of mediocrity.". So you reduce the completion times to "6". This time up to 5 people join up, there may be more people that have that many wins but they ignore joining for various reason. The timer runs out and no party is form.
Finally, you conclude that "I am going to have to accept the scrubs.", and you reduce the number of completions to "1" because you just want to get this thing started. BOOM, the party fills but you still may end up wiping over and over cause most of the members don't have a grasp the fight yet cause of this type of filtering.