(This ended up being sufficiently long that I had to split it into a second post. As you can perhaps tell, I'm fairly passionate about this subject)
Balance for the sake of balance does not make a good mod.
http://www.sirlin.net/ptw-book/intermediates-guide.html
Balance obsession happens primarily because of competition and epeen. A lot of multiplayer types tend to use games (including this one) as vicarious sources of self-worth, and deluding yourself that you have real skill with a competitive game after your competition has been nerfed into the ground, is a lot easier than actually developing said skill and using it. So there is constant, adamant paranoia to make sure that nobody has even the slightest advantage over anyone else, in terms of game mechanics.
I know I suck at this game; I don't try and hide it, and even if I did, whenever I play vanilla with either my younger brother or anyone else, I am reminded of it very quickly. I don't, however, think that anyone else's fun should be nerfed or spoiled in order to compensate for my own comparitive lack of skill. It actually causes me to do the opposite; I look for the most ludicrously overpowered mechanics I can, most of the time, and leverage them like Tony Stark's suit, so that I can still have fun and get stuff done in the game, despite said inherent lack of ability. That, in fact, is the entire reason why everything constantly being nerfed more and more and more frustrates me.
However this is, I suspect, a large part of the reason for things like the Gregtech controversy, as well. There are a very large number of people in the contemporary Western world who, for a wide variety of reasons, lead offline lives consisting exclusively of almost suicide-inducing levels of misery. Generally during the day, they are too busy ensuring that they do not starve, in order to find anything which will allow them to feel genuinely positive about themselves; so they devote what miniscule amounts of leisure time they are afforded, to the less tangible objectives within Maslow's Hierarchy.
Hence, the reason why the gaming community consists almost exclusively of individuals who use said games as a means of obtaining narcissistic supply. Gregtech is, as mentioned, pretty much the quintessential example of what I'm talking about, here; you get to feel like a God if you can master the level of complexity inherent in building the machines within said mod, and Greg gets to view himself as a God for having written it.
You've got to weigh between reasonable challenge, shit making sense, and most critically of all, making sure the thing is fun to begin with. That's one of the reasons I loved XyCraft, even before the machines started coming online, while others were bitching constantly about it. Its fun, it looks cool, and the machines all seem to be built on that grandest of design principles: It Just Works. Liquid storage alone would keep XyCraft in any of my packs, because there's not all this moronic, arbitrary bullshit of having to make a rolling machine, roll up iron plates, make the 3 different requisite block types, and fit them into a few preset sizes. You just get shit you can see holding liquids, like stone, make it between 3x3x3 and 12x12x12, tack a valve or two on there, and hit the valve with your fist. Bam, job done, storage is ready, and you can spend more time using the shit you store, as opposed to dicking around building the whole damn storage contraption in the first place.
Again, I agree with you, one million percent. The problem, however, is the fact that most other people apparently don't.
Another case in point: Railcraft boilers. Realistic? Sure. Enjoyable? For me...not so much. Partly because they're ludicrously inefficient, and partly because they're a little too realistic.
You even run into this sort of thinking at times in the case of renewable forms of power generation which are more powerful
in the real world, (such as geothermal, for instance) but which get nerfed mercilessly in their in-game implementations, because of developers who assume that >50% generation efficiency is always realistic, or that even if it isn't, everything must still be utterly crippled, in order to supposedly make sure that we've always got something to do.
A lot of mod authors need to start realising that having to shovel more coal into a boiler because you've given me a crappy ratio as a balancing mechanism is
not fun. The correct approach is to give me a decent ratio, so that I can get my power system established, and then actually create something
else after that for me to do. Hell, I'm not even like most players apparently, in the sense that for me, Minecraft is primarily about making my own fun. I've noticed that a lot of the thinking here seems to revolve around the idea of structured minigames, (things being "gated," or "tiered," etc) when that is not what I want.
I want to build ore processing, yes; but I don't want that in itself to have the sorts of mechanics that other types of structured games do, in that sense, which as Poppycocks says, is why some mods have things like five different tiers of gear which all add to each other. Base it on real-world engineering; don't make it hard purely for the sake of making it hard. We the players can do that ourselves.