I think there was some redeeming qualities to the arc, great concept but poorly executed in some aspects. I'd have rather seen the attack been as a warning that humans were advancing way to quickly and there were those who were trying to deter there exploration.
We get a very conflicting crew with the desire to get revenge only to take aid with some of the Xindi to stop the baddies. Didn't like Archer volunteering to kamikaze every mission either.
I did enjoy the arc though, finally gave some detail to the characters, some emotion and the ending was great except for Nazi America