There are new printers that make this approach (single hotend, dual/quad extruders) that are commercial.
In addition I think that WE ALL NEED:
1. the filament diameter separate for extruder in the right panel: "EXTRUDER";
2. a GCODE TEXT editor. I don't want to save and open another software, I wanna edit GCODE and look at the change in REAL TIME in the preview window. Repetier do it for free, I think that Simplify is the best software and I want the best from the best.
3. finally a new manual. Is really awful to look at the present manual. No GCode variables (not acceptable I have to came in the forum and search for it), no explanation on the use of Processes, no other infos on any other advanced function of the software. In the web portal the tutos are present: is quite simple to add the content present on the web to the PDF manual.
4. The bug correction about stacking perpendicular walls over bigger objects roof. Is not acceptable for the users to hack slicing process for very simple objects to workaround a flaw in the slicer math. An this is because we pay for it. I accept flaws in free software, but when I buy something I use to work, I want the best I payed for.
5. Please, try to update more frequently or, at least, give us some info on the development state of the next update.
Thanks