The actual problem for me (audio engineer/music production) isn't so much the new machine itself, it's that after /years/ of stagnation, at a much-hyped keynote titled "Hello Again", referencing the original Mac launch, it's the only machine we got, and it's not much better than the machine that came before it.
Essentially what this signaled to me, and a lot of other people, is that Apple has lost sight of the distinction between its Pro models and its consumer stuff. The touchbar is an interesting innovation, sure, but it's better served, at least at first, as a gimmick for their consumer devices. There were a lot of design decisions that add a lot of cost for people in a lot of Creative Professional segments, including Audio and Video production, without really adding that much functionality. Sure you can use the touchbar as a scrub-wheel in ProTools-- if Avid gets around to coding it in. But even that isn't worth the $400 price bump, when most Audio guys have their own DAW controllers already. That now need adaptors.
Furthermore, if you want a dedicated OS X desktop machine for your studio, what are your options? You can pay through the nose for a Mac Pro that has a couple thousand dollars worth of (now outdated) graphics cards that you don't need, along with an extra grand for a rackmounting solution that will convert your thunderbolt ports to PCI for your HDX/Dante/whatever setup, or you can buy a Mac Mini (which is itself direly in need of a refresh) and be severely limited by your RAM. And spend an extra grand to install your HDX card.
So I suppose to answer your question, the rage is less about what the new rMBP isn't doing for people, and more about what wasn't released alongside it.