Buffy the Vampire Slayer is my favorite TV show, ever. In fact, I can't even imagine a day when it won't be my favorite show. That's said, it wasn't flawless. There were perpetual pacing problems, and to me, they seemed to worsen, from season 4 on. Even then, there were pacing problems evident to me in every season (possibly save season 1, because it was only a mini-season, and so I can't hold it to the same standards).
NOTE: When reading my complaints, please keep in mind: Those who can, do; those who can't, bitch on posting boards, then note what I am doing.
In the early seasons there seemed to me more blatant stand-alones, that for me, mitigated the pacing problems. I was fine with the off-pace of season 2, because the placement of the stand-alones made me feel like I was watching two series. I was watching a serial (soap), where the plot started with the Annoying One and the Master, and carried on to Spike and Drusilla, with Angel reverting into Angelus.
The soap served to show Buffy and her friends (and us) what they were made of, what they could do, and where their weak and/or blindspots endangered them. In short, it showed them their shortcomings, such that they could learn to overcome even the most seemingly insurmountable of foes. The revelations about the Little Bads/Medium Bads/Big Bad were paced to be woven into the B plot of each of the core four.
The stand-alones served many of the same character-driven purposes, but from another point of view (or something, I'm having trouble articulating this). The day-to-day challenges the Scoobies faced in the stand-alones used monster metaphor to great effect, to tell me about high school, young love, and family problems. And they served as big breaks in the serial, the soap opera—if you will—such that it wasn't a problem that Buffy and friends went from something silly like Bad Eggs, to the sudden jolt of Surprise, or from the wacky Bewitched, Bothered, Bewildered to the heartbreak of Passion, or from Xander. In a Speedo. Wet. (mmmm) of Go Fish to (arguably) one of the main two points of the entire seven seasons as told in Becoming. I could accept that things had happened off screen, in between any two given episodes. Most of the time, it felt like time had passed. I didn't have this sense of minor plot points being stretched out over hours, and enormous developments being crammed into about a quarter of the time they deserved, in season two.
Contrast that season with season 7. We had a potential stalked and killed by the FE's minions in the teaser of episode one. That continued at least for a couple of episodes. We had The Parade of Big Bads Past in the final scene. The big bad was basically exposed in episode 1! Then we had how many episodes following, with "From beneath you, it devours," hammered into our skulls. On top of that, we were cleaning up our messes from season 6: Jonathan and Andrew's involvement with Warren; Spike's attempted rape of Buffy; Willow's magicks abuse, and flaying of Warren and betrayal of the gang; Anya and Xander's aborted wedding.
Soap fans are fairly patient about not much happening in any given episode, but in part, that's because soap fans generally get five hours a week of story. BtVS was a weekly drama, with only 22 episodes/hours a season. A good ten episodes (approx., I'm too lazy to research this, today), so ten hours, in the center of the season accomplished about as much as was accomplished in season two's two hours of Surprise/Innocence.
Add in the Potentials and McHottie, and all the time spent on misdirection, whether it was Dawn, Not!Joyce, or Pod!Giles, and there was just way too much static. It threw everything off. Then we have to cram in Faith's story (which is very important to Buffy's journey as hero). If I tell myself the story of season 7, it is a good story. When I watch it, I feel a bit like I do when reading an important story, based on a fantastic idea, written by a fair-to-middling author.