We would like to re-introduce the different types of evil, but there's a few different ways of going about it, and we'd like to pick the one which is best. I personally like the idea of being able to mix and match different ability "sets", such as "Deep Ones" or "Undead", as well as sets such as "Advanced Politics" or "Madnesses".
The two core issues are balance and complexity. Don't want to allow overpowered ability combinations (or at least not have them as a default option, perhaps the player could enter into a sandbox mode to use them). We also don't want to have the game simply throw all the abilities into a giant pile which are impossible for new players to navigate.
As such, a basic start could well be having different Gods/Evils/Factions..., each of which has a special set of abilities, and shares a few basic ones (politics, external influence, enthrallment shadows...). If the ability set is powerful by itself (such as the undead) we could then introduce the limitations (the undead couldn't enthrall because it was just too easy if you could use both). We'll have to see.
Different government types would be interesting to play with, and would also come under the issue of being too complex for new players. We were thinking of toggle-able complexity options. For example the base game would have all governments be feudal monarchies, but you could click an option to allow them to become republics, theocracies, dictatorships...
We've no current plans for the worms. We may think of something at some point, but for now there's nothing on the board.