i use alt+tab alot (i.e. quickly). the new window switcher shows only 3 windows (l have a netbook), that's ok except after i press tab for 3 times the list scrolls, and i cannot see anymore which windows are the next in the list. instead i can see two previous windows, which are of no interest to me.
being able to see which windows are ahead (i.e. will be activated if i continue pressing tab) is of more interest to me, because this way i can stop pressing tab exactly on the window i want. right now i'm pressing tab so quick that i often skip accedentally the window i want. this would not happen if i saw which windows are ahead (e,g, when working on win7 i never accidentaly skip the window i want).
i see icons of two previous windows in the list
i see icons of two next windows in the list, the currrent window icon is on the left side of the list of visible icons
Seems fixed in Plasma 5.
That said, if you have a really short screen, a horizontal task switcher like the Large Icons one may be a better use of your screen real estate.