Making mocks is doing something. I don't think it's healthy for programmers to discount the efforts of designers or vice-versa. Now, it's easy to make mocks that gloss over the real challenges or nasty corner cases, but it's also easy to write garbage code that will never be useful to anyone.
The fact of the matter is that there are a lot of people out there with lots of engineering ability and not much design ability who might jump at the chance of implementing something that's been thoroughly mocked and product-ed out.
This is going to be an unpopular opinion on HN, but I would say the need for designers is hugely overblown.
Most of the time the only people I hear complaining about UI design are UI designers. Except for exceptionally bad cases, most people don't care too much what their applications look like.
And most people would rather have a working implementation with an ugly UI than a pretty picture/mockup that doesn't do anything.
IMHO it's the designer's job to make the UI. That means providing the programmer with templates, CSS, and UI related JavaScript.
If all the designer can do is mockups, then IMHO they are not doing their full job. Like I said in the other reply, it's like a programmer saying "I made the DB schema, what more do you want?"
We can all make some mockups in an afternoon. It's not really worth telling everybody about unless you've done something, IMHO.