Few episodes in TOS were interconnected. There was no arc, few returning and no recurring characters (besides the beloved regulars). This seems an unplanned advantage from employing multiple writers concerned primarily with remaining creative. Background details were filled in later by the imagination. The mission of NCC-1701 was stated up front every week, never to change. Seeking out new life and strange worlds - peaceably - is an open-ended goal since there's always more of each.

Satisfying goals can in fact be dangerous to episodic television - sometimes a series hits a goal and subsequently fails. (Maybe that's indeed the reason why.) Galactica finally made it to Earth with the help of a cute genius kid. The new crew swapped colonial vipers for flying motorcycles and the whole thing became a wreath of pretty flowers that smells bad. I can't quickly think of an example where changing the premise saved a show. Audiences don't like stupid changes.

After "The Expanse" we're left with a new premise: paranoid conflict vs. trustful cooperation. Instead of fighting "bad guys" closer to home we'll do it two months at high warp over there. (Don't forget that, without replicators, NX-01 lacks inadequate provisions for long-term excursions. Guess Chef will invent one of those before too long.) We're not even really sure of the actual enemy - what if the Xindi didn't do it? If those misfits weren't responsible should it behoove the Great Warrior to figure that out? Audiences don't like stupid characters either.

And what even if they did do it? Assume things "are" as future guy said. NX-01 locates and Husnocks the Xindi responsible for killing Trip's sister. (Consider this accomplished say, within a few weeks before boredom sets in.) Now what? Does the ship return to the same ratings recipe enjoyed before? Tampering with a series' premise should be no more possible as tampering with the laws of physics. Our attention span has value and rewriting fundamentals reminds viewers that somebody somewhere didn't think it through ahead of time. (Recall the lack of homework as to the dimensions of NX-01.)

"Enterprise" has an abundance of talent. That talent, like investments in familiar aliens, should not be sacrificed to throw in "more action" ("more" meaning "meaningless" most likely). A confusing concept of "Temporal War" (of any temperature) replaced by a simpleton's "Space War" is not a recipe for sparking interest. This sudden shift from peaceful explorer to vengeful exploder means no longer exercising the imagination that nurtured the very success it may now squander.