Spoiler for Possible eps. count of the arcs:
Problem is, even if they cut out those side character's stories, the story of the 5 girl can still span up to 24 eps., and After Story isn't included in that equation yet, that's why there's a big possibility that they'll do a 24+12 or possibly just 6 (we wouldn't like to see a TOEI version of CLANNAD now do we or another confusing AIR?). Anyway, we're on Eps. 12 now, let's assume Kotomi will have 4 episode. So perhaps, it will end on Eps, 14, then Kyou can have a 3 eps. since she's already build up her route because of her constant screen time (we're now 17 eps.), after that, Tomoyo, might kicked some 4 eps. as well, making it, 21 eps., now, we have Nagisa's school life which we can say, 3 eps. See what I mean, the only story KyoAni might tackle this season is about Tomoya's school life. I already cut out those side stories despite I don't think it will be cut out. Oh... I forgot Mei (the blue pony tailed haired loli in OP sequence), anyway, let's ignore her, they showed her, so she should appear later XD
Also, CLANNAD script story > AIR+KANON combined. I think the ratio is 5:4,
assuming we remove the side character's stories... the ratio will be 1:1 which is still big because we're talking about a script that equal's AIR+KANON combined.
Which reminds me... shouldn't this discussion be in the speculation thread?