I think the main problem is the fact that you spent such a short amount of time with it. Of course I'm not trying to convince you that the MBA is the right computer for you -- it may not be, it isn't for everyone. Just like I've come to the realization that Macs are not necessarily the right computers for everyone out there. Nonetheless I can only share my experience. I went from a Blackbook to an iMac, then I bought a unibody MacBook as a secondary computer. After using the MacBook for a while, I sold it to upgrade to the MacBook Pro with better battery life etc; but instead, on a whim I decided to purchase the MBA and see what it was all about. My first few days with it were terrible mainly because the fans were on CONSTANTLY (never once had I heard the fans on my MacBook or iMac). It did not help either that the machine would then slow down and become unusable at times. Over time I realized that this was happening because I was attempting to use the MBA in the same positions as I used my MacBook (on my bed with the comforter, or in my lap with the vents covered) and this just won't work. As Scottsdale says, it soon became second nature for me to just position the laptop in ways that the vents wouldn't be covered and ever since I have rarely had the issues that bothered me (except for doing certain CPU intensive tasks --- mainly video chatting).
However some of your other issues are issues I've never had so perhaps jessica is right about you getting a dud. For example, the battery life issue I have never noticed. It is obviously not the purported 7-hr batt life of the new MBPs (nor is it advertised as such) but it is just as good as the unibody MacBook I had before it IMO.
Hinges have never been an issue for me, I know they seem to break more easily than the other laptops and my friend's hinge did break however I have never had a problem with mine and they don't feel flimsy to me.
Graphical issues I have never had.
I hate all laptop speakers hence I would never bother trying to use them or trying to rate them in any way. For example, the 27" iMac's speakers are much better than the MBPs but I still would never use those to listen to anything worthwhile. It's strictly headphones or external speakers for me.
"the screen is ok" - This is the best screen I've ever had so I'm not sure what this is about. Viewing angles are amazing and I like that it is not overly glassy like the MBPs or iMac (hence reflections don't bother me as much as they did with those two products). The one thing I dislike is that things seem a bit more washed out on my MBA than on my friend's MBP (the colors seem colder on the MBP which I like). But other than that, everyone always raves about how great the screen is on this thing so I'm not sure why you think it is just ok.
"it's light indeed [...] but I could say the same about the MBP" - I don't think you can even compare the weight of the MBA to the MBP so no, you couldn't say the same about the MBP.
I think it's fair that you had your own opinions about the product but the way in which you share them is "extremely deceptive". But some of the allegations you make are either false or limited to your one (possibly defective) experience. I think perhaps you could have come to the forum with 'food for thought' about how you had a negative experience (but again, limiting it to your experience and for your needs), or perhaps asking how someone could help with the issues you were having. But to come and say the product is badly engineered and deceptive and it is irrational that they sell any is a bit ridiculous. Had I read your comments prior to buying the MBA I may not have bought one, so I'm glad you weren't commenting on it back then!
I love the MBA and it is invaluable for my frequent trips but do look forward to potential future updates (hopefully to add more RAM!) and if they could have a different design with ports in a different position that would be great as long as it doesn't involve doing this:
http://4.bp.blogspot.com/_UJm1lSJKEM4/StQmOmpr7HI/AAAAAAAAB_U/H-sSFLKzZcs/Dell+Adamo+XPS+Side.jpg (yuck).