Well, that's a tough thing to answer. The players are supposed to win. So from a certain perspective, most fights are foregone conclusions before they even start.
This is an absolutely critical point that cannot be overemphasized.
Barring outrageously bad luck for the PCs (good luck for the monsters), the PCs should win every fight of equal, or close to equal, level.
Each player's or group's tolerance for this "foregone conclusion" effect will vary.
I can imagine a person saying, "What's the point of D&D at all? The PCs always win." -- for him, the whole game is a foregone conclusion that he doesn't want to play --
and that's fine. Not everyone likes the same thing.
At the other extreme, I can imagine a person saying, "I know that the PCs are going to win, and I don't even want them to be challenged, I just want to have fun beating down the monsters as a cathartic release." -- for him, he enjoys and embraces the foregone conclusion effect --
and that's also fine.
At risk of getting flamed: this really is like the difficulty setting on a computer game. Some people like to play with the difficulty ramped all the way up, so that their "PC" dies easily. Other people like to play with the difficultly turned all the way down, so that only a total fluke or deliberate recklessness causes their PC to die.
Neither of these ways to play is right or wrong. But different people will find them fun or not fun, depending upon their preferences.
Now, in the example at hand, if the groups of players + DM agrees that, once a fight has reached a foregone conclusion, they want to fast-forward past what they consider the boring part -- that's fine. I encourage them to do that. D&D is a game, and games are supposed to be fun. Skip the parts that your group finds boring! (The DMG makes this point; I'm just echoing it.)
I don't think 4e is somehow fatally flawed because of the foregone conclusion effect. That aspect of the game simply is, and each group should figure out how they want to address it.