Here's something about Lang, too.
We have to remember that Dream Theater are writing their own history here. That means that if the guys didn't like someone, like Lang, just because they like his personality or something, they don't necessarily have to be jerks and say, "well, we just got a totally unfriendly vibe from him." If he screwed up a lot, they don't have to say that either, just to save face for those guys out of politeness.
We know how friendly and good-natured the Dream Theater guys are. If they say something about why they like someone, I believe it. But if they say something about why they didn't chose something, I'm expecting them to put it as lightly as possible, or simply switch the reasons all together. I doubt Jordan actually has something against people making the songs their own. More likely, there was a different problem and Jordan or the guys thought it would look better for everyone for them to just put it that way.