CronoDragon, thats an interesting idea, firefall i believe does something like that. But check out the Extra Credit video, the JCPenney Effect, for an interesting and concise (as always) examination of that idea and its problems
Basically, JC Penney discovered that while people say they want fair, when they tried to do honest pricing (instead of huge markups and perpetual sales to make people think they were scoring deals) people stopped shopping there. They didn't want to buy 30 dollar pants for thirty dollars. They wanted to feel like they were buying 60 dollar pants for 30 dollars. Extra Credits sees similar problems with these types of crafting systems. While its more fair, its also less exciting.
I can see the logic in that, but my experience in Final Fantasy XI online told me there's plenty of people who enjoy both types.
Originally, FFXI used the "strong monster drops equipment at super-rare rates" paradigm for MMO loot design. This essentially turned of all but the hardcores that grouped into super elite linkshells to monopolize the monsters and therefore the loot. Eventually, after FFXI's population began to drop off, they introduced new expansions with a loot system that I consider to be perfect: you spawn mini-bosses that have a chance of dropping items that you gather a certain amount of to turn in and get a piece of equipment. The mini-bosses you killed drop items that you can use to spawn harder bosses, which in turn drop items that let you upgrade the equipment you got into a +1, and eventually into a +2 for the next tier.
While this is less exciting than getting a drop in full, it also eliminates the frustration of wasting hours trying to get something you may never get, and turned out to be hugely popular with that subset of gamers that are more than casual but less than hardcore. I believe the most important thing is to provide the player with a sense of 1) continually progressing while 2) always making them feel like there's more to get. By randomizing parts of weapons that, once assembled, you can use to make the weapon you want 100% of the time, you provide the satisfaction of progression while also appealing to that addictive quality of gambling where the player is continually saying, "Maybe the next chest. Maybe the next chest."
So I do think there's a middle ground to be had here. It would also satisfy one of the benefits of ME3's randomization system, wherein you could get an item not currently useful, but perhaps something you can use in a later build. By the time you level your warrior to 30 (or whatever) you may have an excellent build for a low-mid level archer. So now you'll want to play an archer to make use of your loot that you earned, and the cycle continues.