One area of text input that really could do with improvement in Safari is input labels. Especially on the small factor iOS devices, the zoom level after activating a text box is necessarily so high that the input label often goes offscreen, particularly if the labels are (far) to the left of the input. When filling in a series of inputs you end up swiping back and forth between input and label.

Since labels are often tied to input via ID or nesting, it should be possible in the majority of cases to show the label onscreen while navigating forms, overlaid near the input element. I would even have thought some simple heuristics could be used when the HTML does not markup the relationship explicitly.