DiscOH, overall your concerns are well founded. The programmer in me wants to like the game for its cool features such as procedurally generated terrain and dungeons, but the gamer in me sees the flaws, and the flaws are substantial.
The biggest one is character development. I don't understand how this game managed to get it backwards in some areas.
I can kill 50 bats and get fire bats, and kill 50 firebats to get even badder fireball shooting bats. But wait a sec, killing bats doesn't get me loot. Killing bats doesn't get me xp. And the more I kill them, the tougher they get, and the tougher they get the longer it will take me to reach my goal (killing the overlord). I have absolutely no reason to kill bats and every reason to avoid them. Calling the tougher bats an 'unlock' doesn't suddenly make a bad feature into a good one.
Same exact thing with the tier system. Suddenly all the monsters I've been fighting got tougher. Not only tougher, but with each tier they get stronger faster than your best spells can keep up.
Think back to an old game, say, dragon warrior for NES. You're near the starter town fighting slimes. You gain a few levels, use the gold you obtained to get better gear. You feel pretty good about yourself, ready to take on bigger challenges. But wait, as soon as you step out of town, the same slimes you've been killing left and right are suddenly kicking your butt! You can use pretty words to dress up the game mechanic in this game, but fundamentally it makes as much sense as my example, and just as satisfying.
The average computer game goes like this: You overcome challenge, get rewarded with better equipment, levels, xp and whatnot, then you use that to overcome a bigger challenge and the cycle keeps repeating. The very motivation for upgrading your character is some future challenge that you're yet to overcome, usually in the form of a boss. If there's no challenge ahead, or a challenge you've already overcome, you start to ask yourself, why am I gathering these minerals or why am I trying to farm enchants. There's no *reward* for doing it. It's grinding for grinding's sake.
So if you're not challenged, turn up the difficulty, you might say. But wait a sec, now I'm running out of mana constantly and I've been kiting this sea serpent for minutes trying to whittle down its 15k hp. That makes the game more tedious, not more challenging or fun. Oblivion did this with its difficulty slider, and it didn't work.
What about randomness? Isn't the procedurally generated content supposed to be this game's selling feature? Infinite replayability, right?
Not so fast. While it's true that pretty much everything in the game is procedurally generated, there isn't enough *variability* to its content. While each dungeon is different, each cave system looks essentially the same. Same for pyramids or any other building interior. There's some randomness, but once you've seen a few, you've seen them all. The human brain is very good at detecting patterns, and once something isn't novel, isn't unique, isn't new, it's part of an old pattern we're familiar with. It stops being about problem solving and starts being about mechanicity and rote: a grind.
It's easy to fall into the randomness trap. Bigger is better, right? By that logic infinite is best. Well, it's not that simple. Quality is important too. Remember Oblivion? Huge world, but.. every forest looked the same. Hundreds of dungeons? But once you've seen a few of them you've seen them all: Both were procedurally generated. Even the Big Boys can fall into this trap. Bethesda learned from their mistakes and made most of Skyrim hand-crafted.
Don't get me wrong, I enjoyed the 20 or so hours I spent on it, but after beating the first continent I see no reason to keep going.