I'm not sure that putting opposing terrain on opposite sides of the map is necessarily ideal. I personally would prefer to make it look natural, slightly more organically placed while still being shaped by factors like elevation, rain shadow, proximity to coast, and so on. However, a clean map might be a better idea than a realistic one. What do the rest of you think?

I love the idea of your nation. Truly unique. The only things that strike me as an issue is their lack of language (which would make them worthless slaves for any would-be conqueror, since they couldn't take orders or easily be told how to perform tasks they are unfamiliar with). Since they lack any real organization but have the terrain and dragons on their side, they would pose an interesting challenge to fight. When I first read about them I thought that a few scattered dragons and human riders would be easy prey for a well-organized army of a Keeper led by constructs and powerful creatures. But when you think about it and realize that this invading army would be hacking through a dense jungle presumably full of dangerous predators and poisonous plants and all sorts of other things to ruin your day. And while they wander around this unfamiliar and hostile terrain, they would no doubt be constantly ambushed and harassed by the natives.

These dragon riders of yours tread a thin line between between laughably weak and impossibly strong, but I think that they would work. You know, the idea is so intriguing that I might plop my Keeper down by their jungle. Hmm, speaking of Keepers, I still have yet to conceive a good idea for a new one.