I concur about Scrabble having to rely far too much on Speedword during the self-contained episodes.
Certain shows that straddle lend to potentially great excitement. One example, when the klaxxon sound effect would go off during Millionaire and they were about to play for a huge sum.
Whew! could straddle but it was always rather tidy. By that I mean a front game round never stopped with like 37 seconds to play. Whew always started off either with a new front game round or with the bonus game.
I agree with what one poster wrote, about not liking certain games where the time's up bell determines the winner and you can tell by the clock if one player has no shot (Lingo and MG/HS Squares round leap readily to mind.)
Indeed, so long as the content of the show is good, and it doesn't slug along, either format is good (straddling vs self-contained).
By the way, I agree about the tie-breaking puzzle for Classic Concentration, I always wished the squares would have been randomized, rather than starting with #1. That was one good and fun element of Scrabble's Speedword, the letters popped in at random rather than in order from left to right.