Fabio,
Firstly, you should perhaps try to equate the cameras shortcomings with Sony's stated specification on its sales leaflets and on the camera manual. If you decide that its claimed potential cannot be realised then as we would consider here in the Uk, its 'not of merchantable quality' and you might want to return it for a refund or repair.
Secondly, although I am not a digital camera user as yet and can claim no real experience other than borowing a digital camera for a day, your experience highlights why I will not buy one for a while yet. So few of these models seem to have had any real design input. On the other hand they ALL seem to have been heavily 'styled' with marketing potential the main consideration. I get the impression that they don't really need to function well as most users will either be reasonably pleased to get the current gem or will merely move on to buy the next one.
Additionally, all the digital 'toys' seem so way overpriced,....a £200 item for £1500 ! A case of 'a new broom sweeping clean'. Most of the people I know who have bought digital models seem to me to be trying to buy something other than a mere picture making tool and, with respect, you seem to me to be in this group also. Most of these aquaintances have been disappointed to greater or lesser degree, but then, few of these digital cameras have been truly targeted at a particular type of user, they are simply glittering baubles to attract anyone who will buy against a promise of potential,...You said it yourself; "..an enthusiastic person who likes new stuff and the possibilities it can offer.."