If RPG scenario is ever to happen - just add quests/objectives, they fit into RTS idea too.
My point on classes:
· Fixed classes would limit the gameplay;
· "A class" should be a separate tech tree, which is researched simultaneously with main one, and, you can research whole tree. Special science ...

One more thing, and I guess it goes into this thread, there must be an option to reduce or even disable "blinking" effects. When planting big blueprints far away from power source, all those flashing yellow triangles become my nightmare.
Fast solutions that come to my mind are:
-show those kinds of ...

If by any chance this idea is still in consideration, I vote yes.
Cave systems or many planes, even asteroid mining - any of those will do.
But those planes should be very limited in size or game will take too much time to simulate. Just remember how autosave goes ultraslow on really big factories.

Kept track on it for a long time, watching streams, YT videos. Decided to buy as a birthday gift for my very self. First session lasted 9 hours. It was fantastic.
I wish I had more iron

Brief:
It is possible to assign the same hotkey for "same context" actions. Just like this:

http://i64.tinypic.com/2s7jern.png

As far as I could get from tests, de facto SHIFT+1 got assigned only for Quickbar 6.
When I had different items in slots, only 6th slot returned an item for SHIFT+1 ...