I actually liked that Archer was so often out of his depth and had to put on a false confidence. It'd be weird if Starfleet just immediately hit the ground running with an absolute heavyweight of a captain like Picard or something.

I feel like it was a purposeful character choice to have him bumbling around, not really sure what the fuck he was doing, but having to act as if he did for the sake of the crew.

He's meant to be somewhat bad at his job, and regularly confidently incorrect.