It's great to hear that you're fired up about the look of the game! To answer your questions...as best I can right now:
1) Yes - and even at this stage our scenario editor far surpasses our RoN editor. We have had a full time programmer dedicated to that tool for a long time now, and it definitely shows. To give you an idea of it's current state and power, I believe that every map, scenario, and game scene seen thus far has been created with that tool. (there's also a cinematics editor) ...that may not sound like much, but it's quite a change from the RoN days.
2) It will be easy to go in and mod something in the game as that data and art will all be accessible, as it was with RoN. In some ways it will be easier to mod things, but there is a lot more that you can do with our new engine, so that depends on how complex you want to get. There are tons of possibilities!
3) System specs aren't nailed down at this stage in development.
4) There will be something like ages, but that is all based on the size of your city now. So yes, but they work a little differently.
5) Q2 (Spring-ish) 2006