This would be nice to have. Or maybe even more generic, say describe-symbol, which would call describe-function, describe-variable, describe-face, or describe-keymap?
(As an aside, I'd found describe-keymap in one of Drew's libraries - it's basically the output of something like (substitute-command-keys "\\{ido-completion-map}") - handy to have available at times - I have it bound to C-h M-k.)
I like the C-h x binding also (x for the unknown). And something like C-h C-x to jump to the definition would be nice - it could call find-function-at-point, find-variable-at-point, find-face-at-point, or find-keymap-at-point.
I think something like this would make life a lot easier when you're starting out - just a few less commands/keybindings to remember. Especially the keybindings - it took me a long time to learn the different help bindings, and add some of the missing ones, whereas eight functions could be covered by a couple of easy to remember bindings.