#10 "I need you to finish this for me" von einem Kollegen empfände ich auch als unverschämt.
Absolutely, no question about that. It depends as always on the context and tone of voice. I only wanted to point out that the phrase can be used differently in another context, and then I would not consider it impolite.
In non-work situations, I have heard it used quite harmlessly, for example, where practical help is needed.
I'd agree with both #11 and #12. It's stating a necessity, yes, and in a work situation, the correct use would be from a manager or team leader delegating tasks. In that case, the person being addressed is going to take one of of these tasks and is being told which one. But it might not be the best choice.... If the tone of voice is polite then the term is polite. Of course, you can always say things impolitely.