Milan-Sanremo is Gerrans' biggest victory and it was neither dull nor did anybody miss an opportunity.
Gerro worked along Cancellara that day, even if Cancellara was the driving force behind the breakaway's success.
https://www.youtube.com/watch?v=WVHhtp-uWKY
At 0.07 Gerrans counters Nibali on the Poggio (with the strength of the hock)
At 0.55 Gerrans is in the lead, while Cancellara gets back
At 4.48 Cancellara attacks in the final part of the descent. Gerrans had to bridge the gap (with the strength of the hock, again), not "descent master" Nibali.
At 6.33 Gerrans takes the lead
At 7.00 Cancellara takes it back.
The rest is just Cancellara preventing the chase group from coming back. Cancellara made no mistake, it was his only tactic but it was not sufficient to exhaust Gerrans. Such edition shows that Milan-Sanremo is a true major classic and one of the hardest. It has the potential for it but actually if only Cancellara as power man is interested in it, no wonder that it can end up in the sprint someday.
Gerrans haters probably had rather Degenkolb or Sagan winning it while these two truly were wheelsuckers that day (or any day in Degenkolb's case).