[Sai the Dreamer]

About the Ayu arc... I think a good way to put it is with comparisons to Air.

In Air, the first couple of episodes were spent on introductions and getting to like the characters. The next two episodes focused on Kano, though it did come a bit too quickly. Then we get Minagi/Michiru's story for another two episodes, during which Misuzu's state begins to show and develop. After that, it's six episodes of full-swing Misuzu (including the Summer arc - that's just as important).

Contrast this to Kanon. It takes two episodes before Makoto's even introduced. I actually liked the pacing at that point, but over the next 4-5 episodes it just slowed to a crawl. Makoto's arc spanned 3 and a half episodes, which helped give it a full impact, but it could have worked with just two episodes to be honest. Mai's spanned 5 episodes, even better. Shiori's was another 3, but imho it was one episode too long. This meant they only had 6 episodes to tell everything left, from her past, to Nayuki's story, and even Ayu waking up.

They just ran out of episodes to be honest. Had they cut down on the introductory episodes, and actually mixed the characters' development into other arcs (whilst not nearing their climax, of course), it would work a lot better. Something like this, perhaps:

Spoiler for Kanon all episodes:

1-2: Introductions.
3-4: Comedy and hints. Episode 4 ends with the revelation about Makoto.
5: Spending time with Makoto.
6: The end of her arc.
7: Mai's arc begins.
8: The school dance.
9: The first half will be a mixture of 13-14. Second half is Sayuri's incident, and of course, Mai's breakdown.
10: Pretty much the same as 15.
11: And this is the same as 16.
12: First half is Yuuichi trying to convince Kaori, and spending time with Shiori. Second half is her birthday party, and disappearance.
13: The same as 19.
14: Their fruitful relationship, er, blossoms. It'd be nice if he and Ayu went to see Mai/Sayuri at this point, just so they aren't completely shoved off.
15: More AyuIchi love.
16: And more, followed by her disappearance. They get three episodes because, you know, this is the main girl we're talking about! Her disappearing is a big thing. It needs to be built up.
17: Yuuichi grieves, as Nayuki does her normal thing of cheering him up. This is like the happy elements of 21.
18: Yuuichi gradually remembers what he did to Nayuki. This would be the more dramatic version of 21, with Akiko's accident at the end.
19: Nayuki lapses into depression, but doesn't do anything. This is where a major change could work quite well: Bring Mai/Sayuri out of hospital at this point, because we already know they're okay. Sayuri's story goes here, and the episode ends with, "Dedette, Yuuichi."
20: Nayuki's scene. Yuuichi remembers what happened to Ayu and runs up to the mountain, and it ends there.
21: Kaori comes over like she did in 23, and talks with Nayuki. She then asks where Yuuichi is, and Shiori, now healed, goes to save him (remember this would of course all happen in the space of a couple of hours). Shiori then fulfills the real Makoto's role here.
22: The first half of the episode builds upon happier times, just like before. Then Ayu returns for her final farewell. After she disappears, the clock scene. Episode ends with Nayuki's apology, at which point she tells Yuuichi where Ayu is. He runs to the hospital and the episode ends.
23: Everybody takes care of Ayu. Yuuichi figures out about the hairband, and attempts to fulfill his promise.
24: The true happy ending. Akiko recovers, Ayu wakes up, everybody's alive and well. We then get her monologues about the seasons and dreaming, followed by the same ending scene we got in episode 24.

This isn't perfect, but I don't see why it wouldn't work. Plus this way, the other girls still play an important role, and don't get shafted.

The point is that Misuzu's arc got more than half of Air dedicated to it, whereas Ayu's got less time than Mai's (if you exclude Nayuki and Sayuri's stories, respectively). It really was rushed, no matter how you look at it.

Ooh yes, that reminds me. Thanks to Eclipse, SS, TWH, and Sprocket Hole for your super-fast, but still awesome, subs! Really, having two consistently high-quality 24 hour releases (and another that's usually out within a few days) is just somewhat of a godsend. You guys are awesome, and I only hope we'll get the same dedication for Clannad. <3