I don't think I'd really care to do "Yesterday's Enterprise," not unless I could change/eliminate two things:
1) Guinan's magic we're-in-the-wrong-universe sense. It was a lazy plot device to make the characters aware of the change in history, a deus-ex-machina gimmick. Instead I would've had Garrett decide that if they could go back in time, they could prevent this dark future, and have her convince Picard to let her go rather than the other way around. (And I wouldn't kill her off before the ending.)
2) The concept that Tasha's original death was "meaningless." Armus's decision to kill her was meaningless, but Tasha put her life on the line in an effort to rescue her crewmates, and that's very meaningful and admirable. "Skin of Evil" had the guts to show that death isn't some well-behaved, sanitized thing but a real danger that can strike anyone arbitrarily; that was mature and honest and helped create a stronger sense of the risks the characters were taking. "Yesterday's Enterprise" threw all that out the window -- and worse, it led to the totally pointless creation of the Sela character, a concept that was never handled well and just kind of fizzled out.