Present Day
Perhaps they shouldn't have set the movie in the Present Day so much? The present day is *NEVER* the most interesting part of the game!!
And maybe they should have just adapted one of the games. Blag Flag is too epic to do in one movie but maybe they could have done Assassin's Creed or Assassin's Creed II? They could have even recreated Desmond's story, spread out across multiple films (assuming they were successful but hey, they prolly would have been better received than this).
But whatever they could have done, the historical parts *NEEDED* to have been in the forefront.