One of the seats in Colorado will positively not switch back. Redistricting has made it safer for Gardner. (And frankly, I never expected a Democrat to hold CO-04 even if they hadn’t changed it. Betsy Markey’s two years should mostly be applauded for the highly desirable effect of disposing of Marilyn Musgrave.)
And, in fairness, the changes that made CO-04 safer for a Republican–the move of Fort Collins from the 4th to the 2nd) also made CO-02 safer for the Democrat incumbent Polis.
CO-03, the seat that Salazar lost to a Republican in '10, could change back. It didn’t change much, still covering a vast swathe of the southern and western part of the state, including about 20% Hispanic. But it might not change back; it’s still closely aligned among the parties. Tipton does seem to be well liked. We’ll see.
CO-05, and CO-07 are more competitive now, but I doubt the incumbents Lamborn® and Perlmutter(D) will lose.
And, of course, DeGette(D) and Coffman® are locks in CO-01 and CO-06, respectively.
In short, those of us hoping for a new Democratic majority in the House shouldn’t expect more than one seat gained in Colorado, if that.