I agree with this, but I don't see Archer sleeping with Erika as a continued relationship or a commitment to a continued relationship. Booty call = one-time thing.
They had been a couple until he was promoted to captain and she became off limits. They were finally able to resume their relationship because she was of equal rank. It's hardly just "booty call."
I do think the writers had him recover from his actions in season 3 way too soon and therefore cheated the audience from some possibly powerful and interesting development/reactions. For example, I think it would've been smart for the writers to have a character we know already and a friend prompt Archer to help him realize he's a decent human being.
I agree, which is one of the many reasons I hated the stupid "cliffhanger" at the end of Zero Hour. This was one season that didn't need it, and could have gone straight to the scene we got at the end of Stormfront II, Enterprise being escorted home.
Season 4 could then have opened with a two or even three-episode arc dealing with consequences of the events in the Expanse.
-- Hoshi's post-traumatic stress;
-- Phlox's use of the lyssarian larva to clone Sim (a violation of the Lyssarian protocols) only to end up killing him. The Lyssarians learn of it and come looking for his head.
-- Archer's act of piracy in stealing the warp core (representatives of the species come looking for his head because the crew was killed when it couldn't outrun a pirate attack).
-- T'Pol's mainlining of trellium should have come out.
-- ASAIK, Trip never went to see his parents in The Expanse. Maybe we could have gotten a homecoming for him (I've always thought it was ridiculous that we know more about Travis' family than Tucker's).