Tooltips seem to have gone out of style in this touch-first world.
Good UIs still use tooltips, you just have to click or drag when in touch mode.
There's also the awkward problem of most native tooltips being plain-text-only, when text is not actually sufficient for every problem (such as international text). And emulated "tooltip" widgets are slow, buggy, etc.
From what I've noticed, the touch-friendly replacement for tooltips, for elements like form entry, is the info icon (the circle with the i in it). I actually find this to be even more useful than the tooltip (when space allows) because I know there is more context I can get at a glance.
A thousand times this! All disabled menu items and inputs should always have a tooltip or other means of explaining why they are disabled and what to do to enable them, with no exceptions.
