Almost all packs I have played and worked with, and those I have made myself. You simply don't have the time most of the instances to spare any of your 200 mods that you didn't balance your pack around a second glance, much less inpepth testing and configuration. If something looks like its op, its getting turned off, it may or may not be enabled later.
Obviously this affects your mod alot, since alot of the stuff looks op on first glance. Its just a reality of pack development for such packs, though.
Its not meant in a disrespectful way though. Most of the times when you add a mod that you have never heard of its because some player keeps bugging you about it. At that point you expend only the effort of figuring out if something in there would break your balance. That seemingly beeing the case, you disable said item. Ofc you don't have time or energy to do indepth testing of a complicated mod just because some players really want it in.
And ... I'm one of those oddballs that actually try to understand a mod before I use it.
I inquired about RoC initially, when I did hear that it was OP; this was from before any of the major rebalancing things, and it is no where near OP without massive time. Heck, as someone said, you can give yourself unlimited resources and still have trouble making it do things.
A player that I play with wanted forestry. What little I knew of forestry at the time was: Bees make all resources infinite with very little work. Since then, I've learned that the time and effort to breed them is significant, and they actually produce rather slowly. Combined with the serious shortage of princesses, and they aren't that excessive until you've been playing for a long time.
I'm still playing with another half-dozen mods just getting them tweaked the way I want (worldgen in various different dimensions, no dimension has everything -- this server will be based on exploration)
I spent a while trying to understand Steve's carts, and played with it. But I never figured out how to do any of the excessive stuff people said could be done with it. And no one has "Here's how to abuse Steve's carts" websites.
I am curious about Chromatic Craft, which is why I asked. But I actually have too many things on my plate already to add learning it, so rather than try to do a cursory glance, I'm just not including it.
The only mod going into my server that isn't well understood by me first is RfTools. Here I'm trusting that McJty has a decent job of balance in, and the whole idea of "get a massive power source for abusive dimensions" is just a different flavor than "abusive ages have instability" (*).
This is a good question, actually. Can someone name one other mod where the reputation of the mod or the author has been tarnished by people modifying the mod?
How about Flower Child? I'm not that familiar with BTW, in fairness.
(*): I thought I knew how to abuse Mystcraft ages to no end. Then, someone one-upped me. Turns out that a boat counts as shelter from the sun, so obelisks in an ocean age are really cheap.