If you want to be a writer or a journalist, at the very basic, you should be able to WRITE. Understandably not everyone will be able to churn out beautiful prose in the beginning. However, at the very least, you should be able to string a decent sentence together, and it should make sense. If you can't even do that, better consider another career option.
I can cope with a certain amount of grammatical errors and spelling mistakes, however if I am going to have to rewrite your entire story because you can't write for nuts, its time for you to do some serious soul-searching on why you decided to be a writer in the first place.
No doubt some subject matters can be somewhat technical to put across, but that is what your job as a writer and communicator is all about. To take something complex and simplify it for your reader.
What I cannot stand is lazy writers. These are people who make no effort to understand what they are planning to write about, and just load a couple of words together and expect the editor/copy editor to rewrite their poor copy.
Writers should love language and enjoy tinkering with words. Unfortunately too often these days, the people who become writers/reporters, have none of these qualities.
GET IT RIGHT!!
By that I mean your facts, writers and reporters are required to do a fair amount of research as part of their jobs, this includes verifying facts provided by other people. Don't just lump all the information in your article and expect the editor or copy editor to do the checking for you.
I encountered this scenario very often at the last place I worked at as a copy editor. Perhaps as an acknowledgment that their writers were not very good at what they do, the bosses would constantly be at the necks of the copy editors about fact checking. In my opinion, if the copy editor had to constantly call up people the writers had already interviewed to ensure the authenticity of the information provided, it would make the writers look bad for the poor quality of their reporting and ultimately the organisation itself would lose credibility.
The copy editor's job is to make written work look better, add the final polish, cut out unnecessary fluff, make long paragraphs and sentences shorter, write catchy headlines, stuff like that.
So writers, we copy editors are not here to pick up your slack. Your job is to write and get your facts right. Ours is to package your piece for production.