I agree wiith most of your creative ideas Mad Magnus,

 terrain bonuses are indeed a way to specialize citys even more i like the idea of a small fortress city on a mountainsite overlooking the only pass entering your kingdom while behind it are breadbasket citys on fertile grassland or production centers near forrests, as long as this doesnt entail that the map becomes to crowded with citys everywhere, i like to quest even in late games on lands still wild (I really really dislike overcrowded maps in civ or other city building games long live the call of the wild). But with those production bonuses for citys and improvments production overall will increase limmiting the needed amount for citys and stress the importance of well placed citys. (maybe we can even edit the game so dessert citys need to rely on importing food because of there inability to grow it themselves?)

Npcs whom do not believe in the code of honour of kingdoms, should be hostile, ''dumb'' creatures should always attack, and can maybe be calmed by a charm spell of some sort. Like you say let them act according to their lore, but also let them use their mind, kingdom opposed creatures will not wander aimlessly into heavily armed kingdoms, because they might get killed if they do (maybe we could let it depend on there level? See my other post for figments of my imagination) 

I like dagwoods idea for casters to stay in citys, but its seem to limited, considering balancing reasons, maybe every class should have a bonus of some sort; veteran warriors provide training and or defence bonuses merchants provide trade bonuses etc........(this ties in with my former post about city governors with the sovereign when in the capital fighting something like corruption maybe?) 

Quests and the diversity of them seems to be a possibility of the editor already, so i expect to see more diversity in the choises, and otherwise an active community will take care of fleshing out the quests.

Spells and shards are indeed troublesome, and i like the idea of a neutral ''Magic'' shard, wich will be undefined till created,  maybe we need to spend essence to activate (empower) the shard, or change its type (for when you forcefully conquered one?), to make it more balanced? A pure wind mage, only wants wind shards, until he finds a way to add another magic book and or spell that requires him to have fire shards.

For better ideas look at Dagwood, whom seems to be a real rpg player its nice to see wisdom and intelligence and mana and essence (note the over usage of ''and'') but if they do not differ why keep them? spending points in a stat that is barely used results in gimped characters that only have some very high stats countered with empty stats (look at your nearest hack and slash rpg to see the result) 

City improvements are a big part of my earlier post, together with the terrain, and i like the idea of a all important capitol, which reflects not only its importance, the functioning of the kingdom (nationwide bonuses), but also make it stay in one place because of the single fact its important and you have invested more in it then all the other city s combined. I saw the palace shifting between city's, while a palace should be one of the most important and most expensive buildings in the entire kingdom, and that just doesn't feel right . 

About essence in other comments and ideas I red the idea that essence could be locked compared to the level of the character, now a possibility could be that the essence cap could be locked to the level of the sovereign, while the amount of essence could be replenished by (rare?) quests, an example would be a lvl 1 sovereign could have in total 5 essence while a level 2 sovereign has 10 etc, but when he spend essence its gone forever, until he finds a magical stone that attunes him with the land and grants him 5 essence, he now has 5 essence with a cap of 10, meaning that if he finds 2 stones he can only use 1 to fully replenish himself, or when he gets lvl 3 and has a maximum cap of 15 he can use the stone to get another 5 essence filling up his essence bar to 15. (hope this makes sense)

This idea works well with your later post while keeping the difference between Mana and essence intact. 

Another more simple playability idea is for the colour-blind players, I myself as an rpg player like to customise my character but i can see only a limited pallet of colours often resulting in a guy with green skin bright orange hear and a pink cloak (humour's in itself but my character needed to be lightly coloured with red hair and a purple cloak) so please, could you add a little pop-up within character creation that tells me what colour I am selecting? 

If I am not clear or vague please ask  and I will try to better my horrible English.

My apologies for the lengthy former (first) post.

Jasper

Essence

It's good to have a really rare ressource like this. So you can't do everything and you have to choose. Perhaps you could distinguish between 2 uses of essence: 1) Uses the "left" side of the stat that can slowly be regenerated (revieve land, hard magic) 2) Uses the "right"-side of the stat like now that can't be regenerated (surviving defeat, impossible magic).

Pioneer (settler, colony ship)

I don't like this idea because we had it in other games and like stated above we do have a nice way of doing it in elemental.

NPC/ Quest

Yes, we need some kind of alignment.