This is all quite exciting. An Emerald City limited edition just isn't in the cards* for me, but hopefully by the time it's in production, i'll be able to get one of the standard version ones.
Assuming it's as cool as hoped. Seeing the layout, i'm not too worried about layout or flow. My biggest fear is the ruleset; Keith Johnson did the software for LoTR and TSPP, and I found the ruleset on both of those to be mindbogglingly complex, with a wizard mode hopelessly out of reach.

Looking over the playfield layout, what really strikes me is the number of standup targets. There are:

6 on the left outlane
4 above the left outlane (if i'm reading the diagram right)
7 R-A-I-N-B-O-W
6 on mini playfield R-E-S-C-U-E
3 on the witch
1 to the left of the ramp

My god! Thats 27 standup targets, 15 on the main playfield! Are there any DMD-era games that have come close to that many targets? I can't think of any! The closest I can think of to that is Frankenstein with 13 (if I recall correctly).

I do like standup targets, so i'm by no means opposed to this - interested to see how it plays out.

*Specifically, cards like Visa, Mastercard...

Edit: fixed inaccurate reference to the number of targets on The Shadow. It's no longer a contender. Can anyone think of a machine with more than 13 standup targets and a DMD?