I'm not playing this game to fight stuff. I'm playing to build cool and beautiful things. If I didn't consider that a worthwhile end, didn't consider it satisfaction enough to stand back at some point and look at what I build, I would play another game. There are tons of games with a focus on fighting, it is, in fact, one of the main attractions of Minecraft that it doesn't need to be. I do build crazy powerful armor and weapons, too, and what they do is very, very much what I want: making hostile entities less of a consideration. There is more powerful stuff that makes the Wither fight super-easy? Great, I want it!
The challenges I want are of a different kind: creating a working resource infrastructure for a complex base. Doing crazy powerful stuff with the things I have built, like teleporting my base around. Making things look good enough that I can show them off in screenshots and people go "wow". Those are the things I can put effort into and feel good about. Combat - is a chore.
It's great that you want to build just for the sake of building and for building great stuff. That's your view on Minecraft and that's perfectly acceptable.
On the other hand, there's people like me who look at all the building and enjoy it, like setting up difficult infrastructure and building a massive base with a lot of machines running, BUT we look beyond that and also think: What exactly is all this infrastructure for? And part of what drives me to think in this manner is that I view MC as a survival world where I'm supposed to survive nights from dangerous monsters, eke out a living from the land and build my own safe place. At least that's how I was introduced to Minecraft and I continue to think in this manner. And this "purpose" is kind of ruined in modded minecraft where you can obtain extremely powerful items. And that definitely doesn't mean that modded minecraft is a bad thing, it's just that I seek to use the powerful items and "survive" from something only to find that there's nothing to challenge.
While you find enjoyment and pride in building something awesome and saying, "I built that awesome, massive thing there," people like me also find enjoyment and pride in defeating an extremely powerful mob and saying, "I conquered that ugly thing there."
tl;dr While I enjoy building, I also look for a purpose in the building, and find it in surviving against dangerous mobs and conquering them.
In that case, there's nothing to do but to add more powerful enemies by mod. I've heard the higher Ars Magica 2 bosses are pretty scary, challenging even players in powersuits armed with railguns or suchlike (predictably given my preferences, I'm not in a hurry to find out). As I said elsewhere, it's good that all these things exist, but I do wonder why every game has to be about fighting stuff. I'm starting worlds worrying about survival of the next night like everyone else, go on to worry about my home being blown up by creepers like everyone else, but I'm certainly glad that times come when I don't need to worry about that any more and the only enemies who present a challenge are those I must seek out to fight.
So I've got this problem, I love MC, I love having tons of mods, I love all the new content and abilities and powers and machines and everything. The problem is, it all seems totally useless, because the game is so easy! I mean, I can make mechanical armour that is basically indestructible, enchanted with this where I just spam death. Or I can make magical spells, armour, and equipment, and I'm just a walking nuclear bomb of destruction. And all I'm left with is fighting a random zombie, skeleton, or if you add Lycanites, some decent Nether mobs.
I know Gregtech adds a lot of difficulty in terms of crafting, but I'm wondering if there's any mod that makes the game itself more difficult. I want a challenge, something where I actually NEED to use my crazy weapons and abilities. Are there any mods that add a real end game type of difficulty in terms of bosses and mobs and what not? Making the game actually scary again?
What I've noticed is that basically every mod is something meant to be played from the beginning of the game. Like, once you've got stacks of every material, good armour weapons and tools, there's just no reason to do anything. I mean, suppose you've gotten to that point, why would you NEED to start Thaumcraft, Forestry, IC2, or anything else? To get even MORE powerful? For what purpose? There's nothing that can stop you!
Don't get me wrong, I love everything about MC loaded with mods. I go through all the mods anyways, even though they don't help me in any way, just because I love the content. I'm just wondering if there's anything that will make the game hard enough that I feel like getting stronger is actually accomplishing something, haha. Something like Twilight Forest would be awesome, but it's just easy. Like, I played through one of those Nether tower things when I had no powers or awesome gear, and I beat it. Now, when I'm suped up, I can blast through anything in 2 seconds.