I have to agree with the sentiment of "it depends."
Being more of a Star Wars GM, I've seen it where the players have great fun taking out hordes of mooks (be they stormtroopers or battle droids) with a single attack. There's something to be said upon seeing a Wookiee pugilist charge into a squad of stormies and thanks to Cleave and Great Cleave, sending bodies all over the place. Or a Jedi taking out an entire battle droid squad with a single well-placed Force Slam. Heck, even a commando doing likewise with a well-aimed grenade toss.
AEG's ill-fated 7th Seas RPG had a great system for minions which lent itself to "whack-a-brute" scenarios where the expert swordsman quickly dispatches the lesser foes so that he can confront his true opponent (Inigo in Princess Bride wiping out the guards before challenging Count Rugen), and lets the PC showboat a little. And given the game was about swashbuckling heroics, it was a great fit.
Having a Big Bad that's been built up over several encounters go down in a single hit? That's deeply unsatisfying, both for the GM (who spent all this time building the BB up) and the players, who were expecting a dramatic confrontation.
Case in point: From the WFRP campaign I play in, my Knight-Errant (thanks to a very lucky damage roll) managed to impale the head of the Orc War Boss on his lance (dropped him past zero wounds with a headshot and a high-level crit), with said Orc having taken minimal damage (a magic dart attack from the apprentice wizard) beforehand. It was impressive, but in retrospect was kinda "meh." Yeah, I know that such a thing fits WFRP combat (can be very quick and very deadly), but considering this was the guy responsible for the raiding parties that had been attacking several outlaying villages... but at least the GM got a chuckle out of describing just how said War Boss meet his end. Think Steve Martin and arrow through the head
