For me I don't think anime's are being overhyped as much as I am just losing interest in anime altogether. When I first started watching anime I was really into it because it was something new, and fun, so I easily overlooked the flaws in many anime's. Now that I am losing interest in anime I am somewhat over critical, and stop watching many new anime's after a few episodes :/ Getting to the point that I am probably going to stop watching anime altogether. That's just me though, probably not the same for everyone.
I can be just as critical with anime as I can be with just about everything else: though anime has some tropes/problems it tends to fall to a little too frequently, everything else does too. Because it is animated it lends itself more readily to fantasy environments which is one of the big reasons I like it. Also much easier for them to use lots of dynamic pretty colours
Timeslots are a huge problem with anime. Manga suffers this too, but normally to a lesser degree. Pretty often I feel like a weak anime could be a lot stronger just by removing several episodes, or in some cases by throwing in a few more. The standard 12 episodes just doesn't work well for a good deal of plots. I'm not sure if it is a coincidence that most of my top favourites found ways to reduce the number of episodes, or get a few more.
Goodnight for real this time ASF XD
Needless to say, everything gets hyped, anime, manga, regular TV shows, movies, books, games, songs, etc. And when the makers have a big monetary interest, the hype can get extreme.
But hype is necessary, because of the increasing selection of things available.
When everything is said and done, good quality shows through, and bad quality sinks the boat, regardless of the hype. For example, it's fair to say Sword Art Online was heavily hyped. Do you think the hype was worth it?
Also, things go in cycles. There have been anime seasons where I watched and enjoyed several shows, and then there were seasons where very little interested me. And the hype is what usually called the show to my attention.
As for timeslots, it's up to the creators to make an anime fit the appropriate slot. Sometimes they succeed, sometimes not. For example, Gingitsune fit 12 episodes nicely, while Haruhi Suzumiya's Endless Eight arc was a waste that could have been cropped to two episodes. Fortunately popular anime series, like Log Horizon, often get sequels, for those who want more.
In the end, the hype just leads you to the show, whether you watch and enjoy is up to you.