I have seen the future, caves.
You know what the best part of Morrowind was? The caves. Just ask Arkane Studios' CEO Raphaël Colantonio (umlauts are the new goatee, though Raphael has both). Early on in designing Arx Fatalis, he realized that nobody wants to traipse about a large, open world filled with a variety of races, creatures, mountains, and trees. No, no, they want to wade through caves, stabbing a dozen-or-so generic types of enemies for hours on end, with none of that pesky variety to get in the way. Of course, that didn't keep him from totally ripping off every other aspect of Morrowind, but at least he stuck with the whole "caves" idea.
But why stop at ripping off an excellent first-person RPG, when you can also include a totally clichéd plot to go along with it? Whereas shlock literature leans on the opening phrase, "It was a dark and stormy night," to warn the reader that they're about to ingest a totally derivative plot, crappy videogames usually wave the red flag by starting you naked, imprisoned, and amnesiac. When you begin your game and, right on cue, your befuddled, loincloth-clad avatar awakens on the dirty floor of his tiny jail cell, feel free to curl up for a totally unoriginal game. Don't worry about being impressed later on; you won't be.
After crafting some MacGuyver-esque escape from your cell, you can do pretty much whatever you want within the caves of Arx Fatalis. This is providing that you want to kill things in dark caves. See, your prison is far removed from Arx, the only human city, meaning you have to brave the underground caves, fighting fearsome rats and demonic spiders on your way back to the relative safety of the town.
The only tactic you'll ever use is backing off of the enemy while building up your attack's power, before rushing in, swinging, and then backing off again to ready another strike. This type of combat was highly effective when the gang leaders faced off in Michael Jackson's "Beat It" video, and it works just as well during the 20-or-so hours you'll spend in the world of Arx Fatalis. Rats, liches, demons, or whatever, they'll all fall to Jacko's attack every time. If that's not enough incentive to keep you going, you can also waste your time collecting all manner of alchemical ingredients (e.g. mushrooms, roots, and rat poop) to make tasty treats that likely do something unimportant.
You can also search the darkest corners of the world (caves) looking for runes that unlock the cosmic power of magic. The spells range from the awesome "make a light so you can see for five feet in front of you" to the more awesome "shoot a fireball at an enemy that takes off two percent of their life." Despite the plot's insistence that magic's power is equivalent to using a rocket launcher to take down a mosquito, most of the magic that you actually get to wield is closer to waving a sparkler in the enemy's face. Sure, it may screw up their eyesight for a second, but once their vision clears, you can bet they'll go ahead and put a sword in your crotch in repayment. You're better off making sure that your sword goes into their crotch first. Sorry, that's undersells how dynamic combat can be. You can probably stab them in other places, too.
With all of the crotch stabbing, 'shroom eating, and sparkler lighting you'll be doing, you might miss the majesty of the world through which you're traveling. That's not too surprising, since you start in mundane, "been there, done that," brown caves. However, you will quickly outgrow those small areas and move on to bigger, better, and browner caves. Then, when you reach the majestic underground cities, you'll marvel at the rainbows of brown in front of your eyes. At first, you might also miss the subtle sounds of Arx Fatalis. Eventually, though, you'll appreciate the nice echoing of everything. At that point, you might be tempted to be impressed and think "wow, that's a nice echo." When you have that thought, remember how echoing caves have been the standard since Super Mario World was released on the SNES 20 years ago.
I like to start my day the same way. I read my bookmarked webcomics to wake up a little before taking a shower, and then munch on Frosted Mini-Wheats while watching reruns of Voyager. That doesn't mean that I want to spend my increasingly rare free time by playing the videogame equivalent of my morning routine. I expect to be surprised when I pop in a new game, no matter how minor the surprise is. Arkane Studios did a great job copying the source code from Morrowind's caves, but they added absolutely nothing to it.