I wear glasses and light fonts on light backgrounds suck hard. I noticed Mr. Ive doesn't wear glasses – at least in public. May be that's the problem.

As for Helvetica, I have nothing against as it is a fine typeface. A little overused, maybe that's why some trendy folks despise it so intensely. All the typography theory apart, in the end typefaces are all about personal taste.

Anyway, I don't know why they didn't go with something like Univers with configurable weight in the settings app. If they've chosen this path this problem simply wouldn't exist.