Money is plentiful.  It creates a situation were the diplomacy armies are over powered because all you need is money to recruit them.  They best thing might be to limit the number of individuals you can take from each resource.  Only 10 drath (I think that is what they are called) from a drath village, as an example.  If nothing else they should cost more.

Also the dragons and demons should probably cost crystals and well as gold.

I was recruiting champions far from my territory, imbuing them, casting teleport, then removing the imbue.  That feels like a cheat.  Removing imbue should kill the champion, or at least halve their attributes.

There should be an easy way to get champions, who don't have magic, to your capitol.

This is not an anti teleport post. On big map, in the latter part of the game you have to have a way to move armies around quickly.