Version:            (using KDE KDE 3.5.5)
Installed from:    SuSE RPMs

The clear button for all items is unnecessary -- if someone wants to clear it all she/he rather wants to delete the filter. However -- clear should be for each of the items.

Also should be "delete" for each item and then the "fewer" would be obsolete.

The extra row for filter is questionable -- it is useful when creating filter (I admit) but while checking if everything is all right those extra rows (empty) are disturbing, making me think if I didn't miss something. So I would opt for showing only needed rows. I mean -- minimum 1 row, not two, when somebody wants to add a row she/he must click "more". This way every N-row filter would be presented in N-row form, not N+1 form.
So the section "filter criteria" would behave exactly like "filter action" (in terms of showing rows).