Great post. Except that I think Beckett pitched like a #1.
He piched very well against the best/most important teams he faced:
NYY: 5 GS, 1.85 ERA, 34 IP, 38K .941 WHIP
TBR: 3 GS, 0.78 ERA, 23 IP, 19K, .435 WHIP
TOR: 2 GS, 0.84 ERA, 10.2 IP, 15K, .844 WHIP
Against teams with a .500+ W%:
16 GS, 104.0 IP, 1.82 ERA, 93K, .856 WHIP
I would say those are ace numbers, particularly when the total numbers were:
193 IP, 2.89 ERA, 175 K, 1.026 WHIP
I think any team would be pretty happy to get that performance from their #1 pitcher.