Hi Lamboran,
it seems that the A55 would have been more along your line than the A580 
The points (1-3) you mentioned are features that only the SLT models can provide due to their different construction and implementation of the translucent mirror.
1. Digital level gauge in all viewing modes:
This is only possible with the SLT models, because no matter whether you are looking through the viewfinder or on the LCD, the image always comes from the main imaging sensor - always the same way how the image is generated/viewed when framing a shot. On the A580 there are three different ways.
1. The classic way through the optical viewfinder (-> not possible to integrate level gauge there via FW).
2. A small extra sensor that is only used to provide a live image in Quick-AF-LV (-> not possible to integrate level gauge there via FW).
3. From the main imaging sensor when the mirror is flipped up in Focus Check LV (level guage is already there)
2. EVF details:
As the A580 features an optical viewfinder (OVF) it is not possible to have the same information as on an electronic viewfinder (EVF). An electronic viewfinder provides so many more options to display or to hide information, which is not possible on OVF.
3. Video focussing:
With a DSLR it is not possible to focus continuously in video mode, because the mirror is flipped up during recording and the Phasedetection AF sensors cannot be reached. This is the same for all other manufacturers, too. The Sony SLT models are special, because of the translucent mirrow. It does not need to flip up and the fast Phasedetection sensors can always be reached. That's why they have full AF functions in video.
When you use AF in focus check LV with a SAM/SSM lens, you probably noticed that the contrast AF is quite slow and it is pumping to find the focus. This is fine for shooting still images in a studio, but it would look terrible in videos... This cannot be changed via FW update.
4.Quality:
When comparing the image quality of A580 to A55, the A580 should theoretically be a fraction better, because the light does not need to pass through the translucent mirror, but this is not visible in most cases with the bare eye...
Of course there is always room to improve internal JPEG processing, but this was also not offered for A55. In general I am very happy with the image quality and also low light performace.
Regarding your wishes for more picture effects, I absolutely agree. I would be great, if Sony gave the old DSRL users some nice new feature and little functions. I really liked the selective colour when I tried a NEX of a friend!
Cheers,
Jules