I'd love to help with RoM for Civ5, but I feel like it has a lot more elements that are hard coded than did Civ4. Especially once you got to BtS, you had a lot of room (in terms of functionality) to explore new ideas - without having to write tons of new DLLs to support it.
What's frustrating about Civ5 is how linear everything is, and frankly, also considerably dumbed down. Simplicity has its place, but there are ways to have content but still keep things simple. Many wonders are missing (both natural and built), civs, resources, etc. The current Civ5 has loads of promise, but feels incomplete.
With that critique, I think it makes sense to highlight its more appealing elements, e.g. the strategy view. My first thought was "hell yes!" For one thing, I've been a huge fan of Settlers of Catan since I was a kid, and so the strategy view is familiar and intuitive for me, especially when planning out where to plop a new city. Another nice thing is that it speeds up gameplay - even with a fast computer, some of these turns can get a little long. And you just know that as soon as you start adding things, especially LOTS of things like RoM would have, your load times are gonna sink. So having that alternative to the pretty graphics for some planning and all is great, something Civ4 could've used.
Here's a short list of what could be done in RoM(civ5), in my humble opinion:
-More resources, esp. strategic (overabundance of Luxury resources, but strategic are few). Historically, which resources have had the biggest impact on civilizations/regions? Which ones have had wars waged over them, or at least have been a large factor in warmongering? These questions need to be asked. I know all you guys did when making RoM, but when you're dealing with a restrictive framework like Civ5, it becomes all the more important to plan your extra resources.
-Better social systems. I've taken years of political science from the best professors in the field, and let me just say that civ5's idea of society is...well, a joke. Civ4's civics had their flaws, offset by improvements that mods like Revolutions and others made to them, but at least you had options, and those options were fairly accurate in their actual effects on a society. The generic policies system is great if you're a 12 year old newb, but when you're a graduate student who likes history and political science, the latest Civ release fails utterly. The RoM team, I feel, could make vast improvements to this, just as they did with Civ4. I would of course be happy to provide consultation on actual effects of various civic options - it's not like I haven't been graded on my understanding of that some, oh, thousand times.
-Better Great People system In Civ4 (and again, esp. w/mods), farming Great People and having them build wonders, discover new techs, etc. was actually a viable strategy. You didn't have to have some 36 cities like Ashurbanipal as long as your citizens just kicked ass. I've won RoM on fairly hard difficulty settings with just 5 cities and a reallly kickass social system that popped out Great People every other Tuesday. Spawn some powerful navy units and nukes, f**k up EVERYBODY. The point is, in Civ5 you don't have this option. The Great People can't really do much, and so it's silly to even devote any effort to producing them. And the Great Generals? Don't even get me started...
Honestly, the lack of religions doesn't bother me a whole lot. The variability/flexibility it granted in modded Civ4 was nice, but it could get a little hectic. I like some micromanagement, but I think we all have a point at which we just want to focus on some other things besides what our dweeby little Rabbi or Imam is up to. So a generic religious system could still work, unless there was a way to incorporate the vast system of RoM's religions without throwing off the "flow" of gameplay.
The lack of espionage is upsetting at first, but I'm indecisive concerning its inclusion into a Civ5 mod, so whatever: let people who really care about it decide how they want it to be done if included.
RoM is your guys' baby. I'm not trying to tell you how to do the next version, just offering up some ideas and observations. There are lots of opportunities to make Civ5 the best TBS ever, but it will take some extra work considering its highly condensed structuring.