Marking

I have been marking essays for about 2 weeks straight. I'm involved in a project to create a computer-based program that helps students find their grammar errors and figure out how to correct them. My involvement consists of reading about 90 first drafts, highlighting every mistake with the mouse, categorizing the mistake and typing in the correct version. More often than I'd like, I'm making an educated guess about the correct version. I'm also involved in marking about 90 placement tests.

I find that it's not the language mistakes that bother me the most. Most of the test takers don't use English as their first language. What bothers me are the poor thinking skills. These students are in university but I doubt that they could construct a logical argument in any language. Haven't they figured out that most things aren't absolute? I'd like to ban these words and phrases:

We all know...
...always...
...never...
There's no doubt that...
Well, isn't it true that...
Surely we all remember that...