Most likely scenario: Federer will most likely lose to Berdych, if not Monfils. He's very susceptible to power and consistency. Berdych plays Fed tough regardless of what kind of form they are both in heading into the match. And even if Fed somehow did make the finals, Djoko will beat him. Not sure I want to see Fed get beaten yet again by Djoko, or Berdych for that matter. Most likely scenario is Monf takes out Fed and Djoko win 2014 USO. Next likely scenario is Berd wakes up on the right side of the bed and beats Djoko.
Optimistic scenario: We are talking really optimistic here. Cilic takes out Berd and Kei takes out Djoko. Fed manages to get past Monfils, and gets over the line against a tired Cilic. Fed vs Kei in the final. Kei probably won't last 5 sets again this deep in the tournament, but can still take out Fed.
Rating the remaining players for the title:
Djoko - unlikely any of the remaining players can beat him.
Berd - If he can find a way to beat Djoko.
Monfils - Looks on a good run, hasn't dropped a set?
Fed - If Kei takes out Djoko, and he can find a way past Berd. Needs a lot of luck
Kei - Too much mileage already in the tournament.
Cilic - Cinderella story?
Has Berdych lost a set? Monfils hasn't. they are playing great tennis. Roger has a tough draw...
Tier 1(goat): Federer
Tier 1.5: Laver, Sampras, Nadal, Borg