Hey.
It´s just unbelieveable that I had to hunt down this weirdness down to this thread, furthermore I´m shocked that this is a feature and not a bug.
I mean, it´s cool that you´re trying some new things, but this is a well established and muscle-memorized finger movement.
Changing to your idea just alienates potential users and people who´d like to switch.
Please make it at least available as an option, or register both CTRL/Space and Space/CTRL as the Zoom input.
There´s even technical problems with your quirky version:
I´m using a Razer Tatarus next to my Cintiq and have a perfect button layout working with Photoshop, but there´s simply no way to input the CTRL after the Space.
Keep quirky, but in a good way, that´s not it.