I get asked to edit a lot of stuff. Being a native English speaker has its perks, I suppose--for my boss--but it'd be a lot perkier for me if I got a bonus for everything I edit. Nevertheless, since part of my job--hehe, my job, period--is to make my boss look good, I'm a good little minion and edit away.
I'm not going to kvetch about stupid English, because a) my Dutch is just as bad and b) I've seen worse English coming from English-speakers. By and large Europeans have a pretty good command of the English language, and even those who do not know enough to make themselves understood. To me, at least--but then again, I have an almost telepathic ability to understand what people are trying to say. Oh, the benefits of growing up with ESL parents!
No, the bitch-fest this time centers around a whole other aspect of writing: namely, construction and composition. I probably have higher standards than most, since I took so many writing classes in college--well, all of 2. But there were several history and pre-law courses that I took that also required a ton of writing, too. Thanks also goes to somehow never managing to get above a C+ on my lab reports in spite of arduously adhering to everything my "how to write a lab report" guide said. Things that have become second-nature to me--summarizing, careful usage, and making sure things "evolve" in a sensible manner--are apparently not so second-nature to most people.
I don't think it's the language barrier--I really believe that, if things could be written in Dutch, I'd have just as many issues with things showing up in the wrong place, or even worse: again. That's my first pet peeve--repetition. One does not get brownie points for repeating the same thing over and over again. This could be avoided by, say, planning an outline of what you're going to write beforehand.
And that leads to pet peeve number two: said outline, if someone has one, usually has no structure whatsoever. At least, that's the only explanation I can think of when I try to explain why the writers put a particular section "here" as opposed to "there". A good structure allows you to build up a story--it gives your ideas a direction to "evolve" in, without repeating yourself.
It also helps avoid my third pet peeve, which is non sequiturs. That which does not follow. The things which I am asked to edit are often rife with them. And the thing is, I can usually understand why the writer chose to put a paragraph about A next to a paragraph about B, but there's no link between the two, nothing to tie them together.
The last pet peeve of mine is the following: a string of citations does not a coherent point make. Very often, especially in reviews, you'll find that the author strings together a list of one-sentence article summaries, and...that's it. Not even an attempt to say "And what this means is..." See above about non sequiturs.
These problems, again, are not endemic to Dutch scientists. After all, I've read some pretty craptastic shit in the US, too. I guess it's safe to say that I just really, really, spectacularly, hate bad writing.