I think your approach will work just fine. I do both, but my standard setup is what you describe. It also depends whether you always use the Eventide at 100% wet, or whether you have presets that must have the wet-dry adjusted inside the Eventide.
For the former, one approach is to send your dry signal direct from your gtr pre into your gtr amp, then gtr cabs, which would be the pure tone channel. Then you could mike the cabs and send the dry signal into the Eventide, and send the output of th Eventide into a full range PA system, or pwered speakers like Genelecs or JBL EONs or anything really.
You can then use a MIDI switcher to control the wet-dry ratio, and tons of other thnigs since the Eventide is the ultimately MIDI controllable machine.
If you don't want to mike the cabs, then you could split the pre-amp signal and send th wet signal to an cab simulator, that's what Satriani does I think. What I do is simp,y to use EQ to simulate the cab response on my Genelecs. I know it's not the same thing though.
Having said all that, if you send all signals into a quality gtr amp + cab setup, it'll sound great. I use a Mesa Tri-Axis pre, and a Mesa 20-20 into 2 1960A Marshall cabs, with all dry and wet signal, and the reverbs and delays sound pretty good indeed, as you don't get the annoying 10k and above reverb "noise" that full range speakers always have.
