Nemesis is an ok movie if you're not familiar with ST,to me the thing that doesn't make me like it,is that they made it like some cheap clone of TWOK,with the bad guy wanting his vengeance against Picard and the federation,for something they had nothing to do with,when all of his hatred should have been directed at the romulans,and the part where Data upload his personality in B4 kind of cheapen his sacrifice.
As others have said Lore would have been the logical choice for B4,would have open the door to a what if story,who could have possibly stole or conspired with the enemy to give them the "body" of Lore.