Used to be type B many moons ago, now well into type A, but still allow myself some slight type B guilty pleasures every now and then.
Plot isn't all to a show however. Believable characters are important to the whole, as are animations, and many more aspects. I'll take Code's example of C: I liked that show a bit, but it had some major flaws. The first, as he mentioned, were the rather bad characters. The second was actually the plot itself: had a nice setup and beginning, with interesting ideas, but wasn't able to go on well, possibly due to the characters and the time constraints, something which other shows have shared in the noitaminA slot (Fractale most obviously).
And yet, a show might be entirely based around characters, with little plot development, and still be an amazing show devoid of moe and totally not for type B otaku. I will bring Hourou Musuko as a prime example of this, as it was another noitaminA show in 2011, but it didn't have the issues that both C and Fractale had in their own ways. Another noitaminA example of this would be Kuragehime, which had its main interest in the characters and not the plot, but it was still a majorly type A show and was in fact dissed by type B otakus (as selling figures clearly showed, actually).
I'll also go against the grain and say this clearly: Shinkai is not a prime example of type A otaku. He did some nice stuff in the beginning. Then all he did was rehashing ideas, trying to copy Miyazaki, and generally pandering to its fanbase with scenary porn. Its latest movie is an example of this: it really isn't all too good if not for the scenary porn ─ which isn't lacking, as usual for him ─, and the fact he's so scenary porn reliant as a staple makes me think that all those scenes are meant to be there just like moe characters are in a type B show: otaku will like it anyway because it has that one thing they want.
Really, any show could be a type B show if it just has that one major selling point that panders to the people it knows and disregards the rest.
Hell, let's talk about Clannad. People think it's type A. It's not. It's a major fan-pandering with the same-old keyches, featuring moe girls in extreme drama with a hint of supernatural elements. Kanon was nice, it was at least original when it did what it did. Then Key proceeded to do the same thing all over again, marketing its well known fanbase with those few selling points for them and nothing else. And it sold. And it really didn't bring anything new and surprising, which is supposed to be a selling point for a drama: if it's predictable, its dramatic impact will lessen; couple that with the fact that it has only so many comic relieves to break the continuous flow of drama, and you realize why Clannad really got the success it did: giving the otakus the same things they want, namely the usual Jun Maeda work.
It's not so different from the Type-Moon fans who enjoy works more if only 'cause Nasu did it.
Wonder what the most original and interesting work by Key was? Planetarian. Guess what? Jun Maeda wasn't involved. How did it fare? Sold little compared to the other Key works and certainly hasn't seen an anime yet. KyoAni did Air in 2005. Did Kanon in 2006. Clannad in 2007. After Story in 2008. Planetarian's VN was released right after Clannad and we haven't seen an adaptation yet, and now 2012 has started.
We did get Angel Beats from Jun Maeda, which had a surprisingly original initial setup and I was actually quite honestly interested to see how it would go. It ruined what it could have been and ended up being badly paced, still filled with Keyches and predictability, and didn't really do anything with what could have made it interesting and good. Yet it was successfull since many fans still found what they wanted (hi Kanade, I'm looking at you).
And then you have those odd shows like Tatami Galaxy. Awesome characters. Clever directing. Interesting and well-executed visuals. Nice story, not too original by itself, but a somewhat unique take on the Groundhog Day deal. Overall an amazing piece of work. It didn't, however, have anything to pander to the masses, and didn't fare well in sellings. It had a small fanbase interested, you could say, since it had Yuasa's name on it, but, guess what, it didn't pander to them. Because it couldn't. It's just that Yuasa was known to have done different works with different styles, none too similar to the other. I mean, compare Mind Game to Kaiba, and you'll see they're very different, starting from the visuals, ending to the story, passing through the characters. They both were good works on their own tho, that's why some people were interested in Tatami, because the director showed that it could do good stuff without rehashing and pandering, keeping a fresh air to their works still without having to do mind-blowingly original things plot-wise. Hell, Tatami Galaxy isn't even an original work, since it's based on a book (not a light novel, but an actual novel).
And now I'll go back to the beginning example to try and wrap up the end of the post in this paragraph: Control had me and many other people interested because it had Kenji Nakamura's name. Yet me and other people were left disappointed (some outright hated it, I didn't go that far, but cannot say that it was a really good anime overall), because we could see it just doesn't fare well with his prior works (Mononoke and Trapeze). And I think this is the difference between Type A and Type B otaku. The former actually have an educated opinion and watch and try to analyze a show before praising or bashing it. The latter rarely if ever do so, from what I saw, rather focusing on just watching things they like for that reason they like them and ignoring the rest. And it's why many start as B type, and some eventually become A type: one grows knowledge and taste about anime the more one watches, after getting to know the medium well and seeing what it can do and what it could, and it's hard to have this knowledge right from the start.
Pay attention, I'm not saying being type B otaku is wrong: it's just a different interest in the medium. Type B are looking for something else in the medium than what Type A seek for. And there is no better or worse, nor wrong or right, just different, which is why I diss some shows in the way I do while many others praise and enjoy them. It's thanks to the different fanbase that we can have different shows, and it's not like one can quite easily collide into a single anime both of what type A and type B otaku enjoy without failing one or the other. But when it does, well, it does have a pretty big impact, and I can actually think of at a least a couple shows which managed, namely Evangelion and Madoka. Both enjoyed by both types, yet for (mostly) different reasons.