Personally, I just don't want to have to have a combat channeller. I want it to be a viable option for me to leave my channeller in a city, have him be a weak combatant, but have him buff that city while he accumulates essence for the world destroying spell he is researching.
Or, I want to have my channeller imbue a large number of heroes with his essence, making them stronger, and then sending them out to do his bidding, while he stays behind, nice and safe to act as a governor.
Or, I want to be able to imbue a ring or a sword with my essence, making whomever possesses it exceptionally powerful in combat, and then keep that with my channeller as I go out to personally quest, or conquer, or whatever.
Or I want to dramatically enhance my land while my channeller remains behind city walls as a philosopher king, presiding an extremely rich land with a powerful army of citizen soldiers/heavily armored knights/mercenaries defending it.
Pretty much, I want lots of options for how I use my limited supply of essence. Lots of options for how I use my one and only channeller. I want having a powerful combatant, or even a combatant at all, to be an option, but one of many. I want it to be offset by the other options, so there is a legitimate choice for channeller use, essence expenditure, and exactly what kind of kingdom you want to have.
And finally, I want to be able to be powerful without having to paint the land in my color. I should be able to employ all of my non-traditional capabilities (magic, essence, monstors, ect) to be able to create a small powerful kingdom. You have a big army with a huge economy because you invested a great deal of essence into the land? Well that is fantastic for you, but when I use the essence I've been hording all game with my one city with two outposts (created for resources) for a super spell to turn every cow or chicken on the planet into a violent, flesh-eating monster, who will be laughing then? Suddenly that huge army has to defend every city you own simultaniously from a massive onslaught, whereas my small territory is easy to defend.
Leveling, at least right now, reflects improved combat power. Your channeller should not automatically be a supercombatant in order to be strong, therefore he should not automatically be a high level, or attain a high level, nor should that be important for success if you aren't pursuing a strategy that requires a powerful channeller. He could just be really squared away at governing, and the city that he is in is fantastically large and rich as a result.
A lot of "I wants" in here. I say this because I have such high hopes for elemental. This was originally the way that this game seemed it was going, and that is not reflected in the beta at this time. That being said, I understand that just because it isn't in right now doesn't mean it is going to be in. I just wanted to voice my desires for options.