I loved the original vision of WoM (at least my understanding of the vision) -- a world decimated long ago by mighty magics, that our Sovs would attempt to restore using their ability to manipulate Essence to revitalize the land and power their spells.

I saw the vision working something like this (note this is my version of Frog's vision, not exactly Frogs'):

-Empires thrived on the blighted land (the dark 'purple' land) and were penalized on the revitalized land (the 'green'), Kingdoms were the opposite.

-Essence was very limited.  A small amount was available at start and more gained from taking nodes.

-Essence was required to revitalize blighted land (for cities to be settled by Kingdoms) and to power spells (for both Kingdoms and Empires)

The above is simple yet allows great possibilities, for example:

-it explains the greater conflict between Kingdoms and Empires (one gains land at the others' expense), and the relatively lesser conflict among Kingdoms and among Empires.

-it limits city spamming by giving us choices -- spend essence for cities or keep it for more powerful spells (as opposed to the current method of limiting city spamming by limiting valid settlement locations -- this reduces choice, and it's always better game design to increase choice, especially in a strategy game)

-it makes vastly different play styles possible -- one city with very powerful spells/magical troops, to many cities with non-magical troops and relatively powerless spells

-if you wanted more essence you had to go out and take it

-it was a different take on the genre, making the game stand out

The original vision was great.  Unfortunately, it was abandoned long ago.  Essence was removed and then brought back, but a pale shadow of the most important resource that it once was intended to be.  The feeling of a world destroyed that we'd have to revitalize...  Reasons for why there's dark purple land and bright green land... Reasons for why Empires and Kingdoms differ... 

The original vision was a game I'd love to play.

FE seems to lack a strong, coherent vision.  It's more a mish-mash of things, as if designed by committee.  Nothing really stands out.   It's not a bad game, in fact it's a good game, but not the great game that we might have had.