You're saying that our knowing too much about Archer somehow kept Scott from making Archer as good a character as Trinneer made Trip? Please explain. Just because we know a lot about a character doesn't keep an actor from making the most of the role.
No, I'm not.
Having numerous complex, often conflicting, motivations hampers the ability of the actor to make decisions about portraying a character. The more demands placed on the actor, the more likely the performance will be unsatisfactory. That says nothing about the specific complexities of the Archer character, his family history with the Vulcans and the disappointments of his father, his frustration with the hostility he encounters in space, the distrust he receives from his own commanders, etc.
However, if you think that a change of actor would make all the difference, tell us how well you think Connor Trinneer would do delivering Archer's most problematic scenes? How would he look expressing Archer's opinions about the Vulcans (what most posters here call Archer's racism)? How would he look better telling T'Pol he wanted to knock her on her ass? How charming would he be hemming and hawing about the Vulcan HC with Admiral Forrest on subspace? How about surrendering to Phlox over the treatment of the Valakians? Would he be more likable stealing the warp core in Xindi space?