It's all because AoD lacks non-combat mechanics (except for the skill checks, but bare skill checks barely count as mechanics nowadays - it's like saying that you can still call Pong a "game"). No mechanics at all. And that explains everything. Honestly, I myself get pretty annoyed when people compare this game with fallout (because, in reality, it should be compared to Darklands), but let's look at F2's mechanics (hardly brilliant, mind you - the game was developed quickly and by immature designers) and their implementation. So we have this Metzger-Vic-Slavers situation and we want to solve that early and violently. Since you can't beat them honestly at early levels, what can you do mechanically wise?
1. You can steal from people, so you can steal all of guards' ammo & consumables.
1.a. You can also plant explosives (and, at this point, you can have at least 1 dynamite), so you deal some initial burst damage that way.
2. You can lock doors, so you can lock all doors in the guilds, separating its defenders into smaller chunks.
3. You can stealth out of combat, meaning that you can lure one guard, kill him then cut the chase down by vanishing into a thin air. Rinse and repeat.
4. You can befriend gang at the old church, so you can lure slavers there.
5. You can attack at night so their to-hit chance will be lower.
6. You can use consumables on NPCs and there's lots of alcohol to be found in early game, so you can just get the whole guild drunk, then attack. Even better is the jet withdrawal.
See? Game has some mechanics and allows the free usage of them, suddenly, tons of different approaches is present. And mind you, I don't give a fuck that some of those approaches (most, actually) are on the level of Skyrim's buckethead retardation - we're talking about a fucking RPG, not some kind of simulation. What really annoys me about AoD's defendors is that they always use this "realism" schtick to cover all of the game flaws (when it's anything but realistic).
Anyhow, all of that is the beauty of actually working mechanics and that's why Deus Ex was so good - once again, you just had a lots of actually working stuff. Got that "great physical strength" implant? Cool, now you can open an extra path to that NSF-held building. Got that high-jumping implant? Great, lots of extra paths are open for ya. Know how to use your gear well? Enjoy sneaking past the unsneakable situations with those thermo-optics. etc., etc., etc. Whereas in AoD it's always "put your points into skill and pray that developers actually bothered to implement a check for it". Or, more realistically, "spend - fail - reload - redistribute - succeed". What a fucking game!
And mind you, Darklands actually avoided the same pitfall by not being stingy with both skills and skillchecks - you have a party of four (meaning more skills in arsenal), you have saints (which cover different situations), potions (ditto) and, in most cases, you can actually survive the failure (if you wish to). Like, in Darklands, you lose to the robbers - well, they rob you and beat you and that's it, they let you go. In AoD, obviously they kill you because that's what robbers usually do. Of course, losing all of your stuff merits a reload anyway, but that's because this "just don't reload" is pointless - AoD is harsh and your character is almost always skill-starved. Also, there are no opportunities to grind up and catch up. Therefore, skipping/missing each quest makes your character weaker, making that each following quest also becomes harder and failure prone and, well, it's a fucking slippery slope. So sure, you don't lose instantly - but you lose later, it's just that it's dragged out and your time is wasted. Cool.
That's pretty much it. AoD is still kinda cool because it has lots of content (and, as games like Morrowind show, lots of decent content may compensate for shitty mechanics), but it has zero ways to make that content work and, more importantly, it doesn't have nearly as much content as it needs to flow smoothly. And it never will, it seems.
I'm really amused will all this discussion of WL 2 mediocrity and how the codex darlings are so wonderful and perfect. Fallout 1 starts with you killing rats on a cave, then killing more rats on an abandoned vault, then going to Shady sands where you can kill radscorpions or blow up the cave (until this point the combat has really zero challenge or interesting things going on) and rescue Tandy.
So much this, TBH. Fallout 1 is a cute game, but really, the only strong parts of it are the Abbey and the Military Base. Rest is rather mediocre filler (with some occasional gems) which is somehow terribly overhyped (like the glow - one of the best dungeons evah, atmospheric, etc., whereas in reality there's little to do there).