Your real complaint seems to be with the nature of the game itself--it sounds like you want a loot system like World of Warcraft, where you put in X amount of hardcore effort on some quest-chain to get an instant BiS item. Well, this isn't that type of game. Welcome to RNGville, population everyone-who-likes-action-RPGs.
(Feel free to chime back with "No way, I hate World of Warcraft!", but it doesn't change the nature of the loot system that Diablo 1 & 2 established.)
Diablo 3 loot is vastly more random than Diablo 2 loot. For one thing, D2 uniques had no random properties, so were much more consistently good than D3 uniques. The only variation was attribute ranges, and even those were much tighter than ranges in D3. E.g. D3 oculus can roll 33-484 max damage, meaning a good roll is 10 times as good as a bad roll. For another, D2 had lots of ways for you to build exactly the item you needed, such as upgrading exceptional-grade to elite-grade items with the cube, or runewords, or other cube recipes.
Also, compare the D2 version of the uber-boss quest to the D3 version. In the D2 version, you were guaranteed a unique charm with guaranteed useful stats. In the D3 version, you have a random chance of getting part of what you need to craft the hellfire ring, and when you do craft it, you get a ring with mostly random attributes, which mostly is going to be worth little.
Let me try to estimate the chance of rolling a valuable hellfire ring, neglecting the useless proc and the 35% exp gain, since the usefulness of that depends a lot on who you ask. (Personally, I want to maximize my character's current power, not future power, so increased exp gain is only marginally useful.) Then the ring counts as having 2 useful properties (since 170-200 to a stat is basically like rolling 2 useful stat properties), and 4 random properties (which roll at ilvl 62, compared to ilvl 63 for all other rings which drop in inferno under MP in 1.05). Rings with 2-3 useful properties are worth about 5-10k on the auction house, i.e. worthless. On a hellfire ring, you really need at least 2 of your 4 random properties to roll affixes people actually look for on rings (i.e. damage, crit damage, crit chance, attack speed, all resist, vitality, or life on hit) or it's basically trash, and even then it's only comparable to a 1-2 million gold AH ring. With 36 possible properties, your chance of getting at least 2 of the 7 useful properties is 15%. The chance of getting at least 3 is 2%. And even if you roll the right random attributes, you still need good rolls so you don't wind up with something like +17 life on hit.
For someone who is already using a ring worth a few million gold and who doesn't want to trade power for increased exp gain (like me), there's a 98% chance any hellfire ring I craft will be worse than the rings I'm currently using. I'm already planning to buy new rings to upgrade once 1.05 goes live and improves the affixes on dropped rings, since my rings are really not that great.
From where I'm standing, the hellfire ring quest reward seems pretty lame, since it's far too random to be a good reward for how much time you have to put in to farm it (especially if you can't farm MP10, and have to farm ingredients in lower monster powers where there's only a chance of getting keys/ingredients to drop). Compared to D2 where the similar quest guaranteed a good drop, and it's no wonder that people are frustrated. Since it's BoP, unique equipped, and rolls affixes at ilvl 62 (compared to ilvl 63 for other inferno ring drops in 1.05) Blizzard could easily take out some of the randomness by replacing 1-2 of the random affixes with guaranteed useful affixes without significantly affecting the economy or giving the ring automatic-BiS status.