Really quite a brilliant game.
Shame about the unsatisfying end, though. Perhaps we'll see the continuation of this series soon?
I must say, of the character roster, I like Vadim the most, Tevoran secondmost. They're both so blatantly outside of the norm, not to mention having some wicked abilities (Vadim's Bragging and Tevoran's reactions came in extremely handy). Holding the honorary third is Casimir, who's so calm and peaceable amongst Tevoran's predominantly [blood]thirsty gang, whilst maintaining a very tricky, dead-useful handful of abilities.
Although I wasn't in love with Ysabel, she was a pretty handy character as well, with her ranged disabling ability and all. Her melee needs tweaking, though, seeing as no enemies were lining up to tagteam her in a way for her Dirty Knife ability to come in handy. Quite honestly, Vadim being a Stealth-Tanking, stabhappy bull in a china shop did more with his melee than Ysabel did with her all the way in the rear. Maybe give her a rapier or sabre to help her play to her ranged advantage?
Speaking of improvements, I found Ivan needed some tweaks. I've always loved polearm characters in tactical type games, but in this game he seemed a bit vulnerable. In the beginning he was pretty useful, but as the game went on, he just weighed down the team more and more, whilst in other such games the polearm character flourished and was the very tip of the spear (pardon the pun) in whatever offensive I launched.
What I think he needs is maybe a little widening of his field of contact- i.e: allow him to strike enemies that are not in the strict four cardinal directions. Also, I think giving him a minor ranged ability, like a pistol, as a special ability or something, would help him fend off more wily opponents with a lot of movement/energy like the those Bladwort Brothers.
Otherwise, the balancing seems perfectly fine to me.
On the ridiculous side of suggestions, I'd suggest a couple of things, in no particular order of relevance/importance.
Some sort of secret unlockable character ala the Harlequin from "Assassin's Creed: Brotherhood" or the Dark Knight class from "Final Fantasy Tactics: War of the Lions", perhaps as a reward for a good performance thus far in the game or for finding a certain secret[s] hidden throughout the game?
Randomized levels? Of course, this might weigh down your game and/or piss some players off, but it seems like a fairly interesting idea. Granted, this is done in more singular character type games like "Diablo", but it would be a fun experiment to do something with that in a tactical melee type game like this.
If the characters' appearances were subject to change, be it major or minor, influenced by the player or following the ingame plot, or perhaps even totally random! It would be fun to see an Ivan with green hair, a svelte Oksana, or Vadim suited up like a "Clockwork Orange" droog properlike (on that note, it'd be pretty rad if you can find more opportunities to give a nod or two to "Clockwork Orange" or other cult films). Just a thought...
Also, if you could make the various weapons equips discernible beyond just stats, that would be nice. I can't tell you how disappointed I was to see that Ivan's weapon didn't look any different from his original spear and the Baclav (?) spear, although they're clearly very different weapons (as far as I could tell when the guards had it equipped and when Ivan did), This might chew up a lot of your time, like with the randomization engine thing, but I think it would add to the fun in chapters down the road.
Finally, I wanna suggest dialogue/action choices. Although it's a big -- oft annoying -- craze in the gaming community, I think it would have some potential in this series. This is yet another time-consuming idea to carry out, but I feel that it's all the more immersive. But that's totally up to you, whether you wanna go the storybook type route or the player's choice-driven plot narrative route.
In any case, even if you don't take up any of my suggestions, I'll have lots of fun playing future installments of "World's End".