I've read quite a few reactions to the game, and what people seem to like most about Book III is exploration design and puzzles. Nobody says combat is the best part. So if you make combat more difficult people will probably not like that.
Personally I find it very dependent on how it is set up. Is the combat tactically interesting or not? In some dungeons in Book III - Emayu Witch Lair, Seawarden's Guild, Akadai Underground - I thought the combat was interesting. Dungeons have the advantage that you can play with light/dark and space restrictions.
Fighting the goblins I didn't find interesting, all you do is draw one out and then spam your main attack. Since there are so many of them you have to do this over and over again.
I thought the Borehead Beetles and the Trolls in Book II were more interesting opponents, in both cases the landscape helped to create more interesting combat situations.
BasiliskWrangler has never put more than a few dozen of the same monster in, and I believe that has been for the best.
Balanced between the different skills Eschalon has never been, and in Book III the balance is probably worst. Melee units have a difficult time, as they take a lot of damage, and Book III is a bit too short for developing great defensive skills. Just adding to the game would help melee units, as there would be more time to find or buy good armour and to develop a good Alchemy skill for imbuing your armour.
Right now in Book III your toughest opponents are the goblins, but you already have to face them when you're level 10 or 12 or so, many players feel they're not quite ready for them at that point.
The game has a bunch of skills to choose from, and at Macross point you can buy pieces of armour of 15,000 gold apiece, but in normal game-play a lot of this is inaccessable.
This is one thing that makes mages so strong; they don't need that access; they get a good attack skill for free at the start and they don't need much more to finish the game. In Book II melee units would address the balance as the game went on, but in Book III the time is too short for this.
In general I find that in Book III the time is too short to develop additional skills like Hide in Shadows, Skullduggery, Alchemy, Foraging and such. This is a main point of criticism of mine: Eschalon's character set-up screen promises a rich character development, but that hardly works in the actual game. I think the system of character development is okay, but it needs very rich and well thought out game content to do it justice. It wasn't too bad in Book II, but Book III is struggling in this respect.
Another thing that bothers me somewhat is that there's a great arsenal of weapons in the game, but it remain mainly nice pictures of weapons, the extra damage they do is so limited. The damage of good weapons could be increased, along with the strength of monsters later in the game, so that an upgrade of weapon at some point would become interesting. Right now you can just keep slogging away with that same weapon you found at level 1. It does little damage, but the damage you do is mostly based on stats and skills anyway.
If Eschalon had been more mod friendly, I think a lot of these things would have been addressed already. The toolset is coming rather late, and I'm not sure how powerful it is. It can be a very strong point for a game to have a good toolset delivered with it. It keeps players attracted to a game if they can play, manipulate, set their own rules, incorporate their own ideas, write their own stories.
Too few games come with toolsets nowadays. A game to watch out for is Divinity; Original Sin. I think they've got the right idea at Larian Studios. An isometric RPG, turn-based and with an editor included. When was the last time that happened? Big publishers don't seem to believe in that type of game. I wonder why; enough game fans want it!
I guess I'm starting to stray off topic now, so I better stop here. I'm certainly curious to see what kind of maps fans will come up with, especially Finnish fans of course.
