If Avengers 2 (or even better 3 after giving Renner a chance to flesh out the MCU hawkeye a little more) doesn't have the Hawkeye Ultimates scene where he flicks hang nails through peoples eyeballs and then picks up two M4s for the first and the security guys just shit themselves out of fear ... it's a wasted opportunity.
Such a great real world version of Hawkeye in Ultimates 1 and 2.
And Thanos is an Avengers 3 villain for sure. They will need the guardians, Avengers and a lil Scarlet/Quicksilver backup to deal with the mad titan, surely.