Okay, I got a chance to play some more. I'm pretty sure I've seen most of what the game has to offer feature-wise. The preview below is lengthy, so just read the parts you care most about... or skip to the conclusion. There are next to no spoilers.
Character development: Your knights have 5 basic stats, such as Fighting (their own strength in melee), Reign (how much gold they earn you and how much they lower the upkeep costs of your units) and Loyalty (the morale of the knight and his troops. Your knights have classes. I have a Warlord, a Champion and some dude I just got so I can't remember his class. When they level up, they gain one skill point, and you can use this to learn new active skills (such as Dragon's Eye which negates penalties for fog on your archers) or passive skills (such as Holy armor which shields your units). There are lots of skills - 15 for each class roughly. You gain XP after every battle - and ALL your units gain XP, even a basic unit of footmen. The basic units can level up in melee, defense, archey, stamina or devotion, the last of which lowers their upkeep-cost.
Management: Seems pretty okay, so far. You conquer cities and special areas (such as Stonehenge) within each province. These give bonuses and sometimes recruits are available (recruiting is the main way of expanding your armies). Units cost gold, and consume food and cost upkeep while you have them. Each turn consists of a season, and true to the arthurian universe, you rest in winter. So you can't attack in winter. Summer, autumn and spring all offer different bonuses/penalties depending on your actions. Winter is where you level up if any units gained XP. You also pay upkeep and that stuff in winter. While this all could be a staple of the series, I'm having lots of fun managing my little part of Brittania. It's horribly impeded by the GUI, though (see below). One of the innovative parts of this is the round-table screen. Here you can manage your knights, dismiss them, find wives for them (raising their loyalty), torture enemy knights you've captured, release them for ransom, kill them, and that kind of stuff. What I'm worried about is the recruitment; it seems you have to visit each city when recruitment is available, to add the forces to your army. While maybe realistic, it certainly isn't fun. It seems much a la returning to your town in heroes of might&magic; wasted turnes spent moving, recruiting, ending your turn, and then get to actually play.
Quests and objectives: There are two types of missions. The objectives are basically; "do you want to side with bad king or good king, christian king or old-faith king." Then you fight whoever you didn't side with. Sometimes it's a little more complicated, like: "Which city will you claim as your Stronghold"? Quests are a lot more original in this type of genre. They're basically little text-based minigames, where you meet several skill challenges. You encounter something on the overland map, read the quest, and then choose which knight in the army that encountered it who'll do the quest. You then have several options to how you will complete the quest. The options you have are based on the skills of the knight you chose. So some options are greyed out (if your knight doesn't have the skill) or red (if he will fail because his skill is too low). When the quest resolves, you gain rewards such as XP, CAREBEAR/EVUL points and so on. The C&C has no effect on the storyline, as far as I can see, except in terms on the morality-wheel. Besides that it only matters in terms of reward/how much effort it takes to get through the quest. For a game of this type however, I'm more than willing to forgive this.
For example, I sent my diplomatic knight on a mission, and only completed it by paying 2000 food to the resident lord, because I didn't want to use the Tyrant-option and I didn't have enough Christian-points for them to just trust me straight ahead. In the end it earned me a CAREBEAR-point, some XP, and so on.
The next quest I sent my fighting knight. I conviced a group of soldiers to join me, but only by claiming them in Christianity's name. My diplomacy was too low to convince them to join freely. This lowered the morale of the whole army, but granted me the units and some Christianity-points.
It's entertaining enough, and if it keeps the same amount of options throughout the game, it's definetely worth my time.
The writing: Is pretty "meh." It's your classic King Arthur setting, but I'm very thankful it's less "CLIVE OWEN WILL TEAR OFF YOUR BALLS!" and more the original saga. The setting is fucking solid - the writing itself not so much. As for how much you'll see; you'll see it in quests, objective-descriptions, the notes on storyline supplied by your advisor and small notes. There's also a story-compendium explaining what goes on. Kindda like the codex from Dragon Age. It's an okay read, but don't expect novelty.
The fighting: I don't know much about this, since this is my first wargame of its kind. I'm having fun, though. In my earlier post you can see how much has an effect on the outcome, and it really does. In my first "hard" fight (meaning outside of the tutorial battles), I fought the fae people for the first time. I was utterly crushed on my first three attempts (playing on normal), until I hid my archers in a forest, flanked their light infantry, and wedged into them. My archers got in a tricky situation because they had wargs, which were damned fast and broke off from the main battle as soon as they realized I had archers. I was too slow to hunt them down, so while, overall, I beat them soundly, I lost 3/4 of my archers in that battle. Damn. Maybe someone with more experience on wargames can give a better assessment of the combat. The only really bad part of the fighting is micromanagement. You can't just put your light cavalry in your heavy infantry group and move them at the same time, for example. If you do this, the cavalry will storm ahead all alone, because they're faster, and thus get killed in an instant. It's incredibly annoying that they won't wait for the rest of my guys, like in every recent RTS-game. You can do the CTRL-#-thing, but you'll want 5 or 6 groups in the large battles, and that gets a little tedious. The battles are RTwP however, so you can do the micromanaging while game is paused.
The GUI: Holy fuck that shit is confusing. Not only because of all the options. But the layout too. It'll take some time to get used to. I still misclick and stumble around in it after playing for 2-3 hours. It must've been hard making a GUI that could support everything you can do in this game, but shit. There is no intuitivity. It took me 15 minutes to find out how to split an army. It's easy enough to use once you figure it out, but there's no reason you shouldn't be able to do it from the armyscreen itself; instead you do it from the overland map by bringing up a menu-wheel. The same goes for the round-table screen (managing knights and so on), though it's more intuitive than stuff revolving around army. In the battles themselves it takes time to figure out the GUI too; withdrawal is extremely important for saving your knights, and you have to click a disengage button first. You can't just run away. They did this because pressing this button lose you some of your army, which is fair, but they could've implemented the withdrawal to the action of fleeing itself.
Conclusion (level of potential): There's potential for a gem, I think. But main worry so far is that the battles themselves will become really repetetive. If the character development is done right, this may be thwarted somewhat. I'm a bit pessimistic though. The management is the same deal; if it continues to surprise me with its complexity I'll call it a gem, but if it presents me with more carebear/evil kings to choose between, or quests that are handled by a) giving 2000 food, b) threaten or c) use diplomacy, it'll probably get really repetetive.
All in all though, I'm already certain it was a good purchase. I support the effort, which is considerable, no matter what.
My ability to judge the game is heavily diminished by the fact that this is my introduction to the genre, so I'd like to hear some thoughts on it by someone who's strong in stuff like Total War. The GUI, for example, might be something the whole genre suffers from as far as I know.