Hmm well I was asking kind of rhetorically I guess, to see if people agreed with me that duping was not a good idea.
But, no one seems to worried that blaze rods can be created infinitely in FTB Ultimate, so I thought people really didnt care about 'duping' much. Interestingly I joked with my friend on our server that my family took me away from the game and that he and our other friend were 'way ahead of me'. His response was 'it's not a competition'. But it IS a competition of sorts, so duping is really not a good thing.
Really though, minecraft kind of diverges from other ways people compete. Like many online games, it often just comes down to the Time you are able to invest in it. I have a family, my friends are all single that play minecraft with me. They get way ahead of me in terms of mid game/end game stuff and setups.
i kind of consider EE3 to be 'duping'. 4 iron for an ender pearl? is this really much different than me cheating them in to get Tesseracts going far, far earlier than the TE mod creator probably intended? And the blaze rod exploit, turns a valued and hard to get resource into something about as valuable as iron. Maybe.
Two points first:
1. Yes, duping is bad. I've used it, but typically in circumstances where the extra time required would have netted no extra enjoyment, and there were no rules (typically play by myself).
2. There is/was an interaction between IC2/TE/AE/etc and EE3 which allowed theoretically infinite blaze powder. However, after the nerf to boilers and the like, it is not spectacularly helpful early game, and late game, there are other, more continuous methods (Soul Shards, MFR Autospawner, etc.) It's know, but not considered to be significant, especially with the relatively low number of recipes that require blaze rods (ender chests, brewing stands, and not a whole lot else, magma creams, maybe).
The philosophical point about letting people get ahead of you and the time required in game for progress is an interesting one, with regards to balance, and one that many games struggle with on a continuous basis (see free-to-play vs. pay-to-win games).
The EE3 ender pearl from iron thing is not a dupe in any real sense. There is no closed loop. The ender pearl cannot be used to make more iron, so you always need to find that to begin with (granted, it's relatively plentiful, but still). To my mind, I quite like it, as it bridges a gap fallen into by a lot of mods. As far as I know (because it makes sense in my head), most mods use ender pearls in their "teleporting stuff" recipes simply because it makes narrative sense. Endermen are the only things in the universe able to teleport, so you need to use their drop to take that power. The pearls also allow you to teleport, so that must be the source.
This is fine, except for the fact that, in my experience, ender pearls are damn difficult to get in the overworld. Wandering around beating stuff up, I'm typically lucky to get one enderman sighting in a night, plus they have more health, hit harder than any other mob, and they teleport. This is one of the main reasons that the End is supposed to be the End. It's tricky to get to, and the boss is troublesome. However, the items made from ender pearls have much more use both in conservation of resources, time and server-power, that it's dubious whether they should be left to end-game. I don't mind piping all the stuff back from my quarry, but it's a pain to move, chunk-load (another ender pearl recipe, by the way, and magic, therefore pearls), and causes stupid amounts of lag.
It's something that doesn't necessarily fit into the EE3 sequences (such as iron>gold>diamond), but it's something that's valuable in bridging the gap between narrative sense and not being a ballache to do.
To OP, I can't seem to see anything about dupe bugs in the CC changelogs (or at least searches, I've not combed through it). Is this the same one that costs a bucket of oil to pull off?