I have been playing quite a lot of Tekkit and I have found an easy strategy for getting tons of diamonds or Dark matter. It uses a cow and takes very few resources to build. Building it spoils the game very fast. And getting the Swithwolf's rendering eye is way too easy too.
With just 2 hours of playing I was able to get all of EE's items.
Transmuting stuff removes the need to too any work at all. If you have one of any item it's way too easy then to make a punch of them.
If possible make EE items more expensive.
I saw this contraption online from: http://www.youtube.com/watch?v=Zo1kr6Hzk0w
This machine makes about 1000 EMC per second. Building only one side of this machine produces enough to make lots of diamond blocks.
Possible solutions: Make a limit for how much you can milk one cow and how much stew you get from one Mooshroom. There might be more ways you can generate infinite EMC that I don't know yet.
I know many people will say that I shouldn't build this thing if I don't like it, but on large servers it makes the game very unfair if people build these things.
(Please consider doing something about it!)