This is very freakin' impressive and I can tell that a lot of work is and will be going into this.
I really like all the ideas you have (digging site; elemental areas as opposed to mixed terrains etc.) and I am absolutely looking forward to seeing this all happen!
I hope that you can finish this some day and it won't get abandoned at some point, because of how complex it is. I'd be sad, because your ideas have a lot of potentials. I am aware though, that it's a lot to do. Kudos, though. =D