As a teaching professor, I read a lot of papers. In those papers, I see a lot of wonderful writing, and a small amount of terrible writing. I spent a fair amount of my time while reading these papers correcting grammatical errors. Some of these errors are things that absolutely must be fixed. You do need to have complete sentences. You also need to have subjects that agree with verbs. In academic writing, the rules are rigid for a reason. However, there are a couple of rules that I would love to see fall by the wayside. Students, if you’re reading this, the answer is yes. This is your permission to ignore these rules when writing papers for me.
1. Never use passive voice. This is one that every professor loves to browbeat students about. “It should be ‘The teacher decorated the classroom,’ not ‘The classroom was decorated by the teacher.'” Yes, it is commonly recommended that you avoid the passive voice in favor of the active voice. In many situations, defaulting to the active voice makes sense. However, sometimes passive voice just sounds good! There’s nothing wrong with tossing a little passive voice in your writing now and then. For example, the sentence “Dr. Seuss books are loved by millions of children around the world,” sounds great to me! A little passive voice here and there adds variety to your writing, and when I’m grading my 60th paper, I’m more than ready for a little variety. This doesn’t mean you should apply passive voice willy-nilly, but a thoughtful application of passive voice can make your writing more interesting.
2. Never use “they” when referring to one person. Maybe this one made sense 150 years ago, when men were publishing about the work of other men, and everyone fit into a neat little gender box. In modern times, though, if you follow this rule you either have to exclude a gender or you end up with clunky writing. I find “he or she” to be disruptive of the flow of reading, and it’s still supportive of the gender binary. Not everyone is a he or a she. I’m all in support of adopting “they” and “them” as singular, gender-neutral pronouns. We use this language convention all the time in spoken language, and it’s time that it was accepted in academic writing as well.
3. You should always put one space after a period. No, wait, you should always put two spaces after a period. People get really up in arms over this one. I’ve seen entire articles written lambasting writers for using two spaces after a period, and yet the APA guidelines require two spaces after a period. What is an academic writer to do? How about whatever you want? In this day and age, is this really an issue that is worth spending time and effort on? If your manuscript is getting published, the editor can space it how they like. For anything other than published manuscripts, however, the micrometer of difference between two spaces and one isn’t worth anyone’s time to correct. If you do think it’s worth correcting, perhaps you need something else on which to spend your time.
4. Never end a sentence with a preposition. Many times, this one makes sense. However, there are also lots of situations in which reworking your sentence to avoid a terminal preposition just makes your sentence sound terrible. This is another example of modern spoken language having solved a problem that written language is still wrestling with. No one is going to say in spoken language, “To which schools are you applying?” We would say “Which schools are you applying to?” And yet, all to many professors whip out that red pen at any sign of a terminal preposition. Good grammar should make writing more readable, not less readable, so put those red pens away.
5. Never begin a sentence with a conjunction. If beginning your sentence with a conjunction results in a sentence fragment, then by all means, rework your sentence to avoid the beginning conjunction. In my opinion, though, the fact that one of these sentences is correct and the other isn’t is arbitrary:
However, I do not think standardized tests are effective.
But, I do not think standardized tests are effective.
The words that begin those two sentences mean the same thing, so why is one acceptable and the other isn’t? If you guessed “archaic grammar rules that have no value in modern academic writing,” then you get a gold star!
6. Make sure to always write in academicese. Okay, maybe this one isn’t a rule, so much as an apparent unspoken agreement. There seems to be some vast conspiracy among academics that the more 50 cent words you use, the better your writing is. No, no, no. The purpose of academic writing should be to convey ideas clearly and concisely. I can’t tell you how many published papers I have read that required me to translate from academicese to plain English before I could understand the points they were trying to make. I have a vast vocabulary, but I don’t want to have to translate your writing before I read it.
photo credit: Lívia Cristina via photopin cc
edspiration.net 
I completely agree that the passive voice does have its place in academic writing, especially since this is a neat trick to add some variety. One of the times that I like to employ its use is when I would want to write two consecutive sentences with the same subject. For example: “Sam punched the wall. Sam hurt his hand,” becomes “Sam punched the wall. His hand was hurt by the blow.” or something similar. This way, if I want to keep my subject, I don’t have to sound repetitive. But, like you said, the passive voice should be used only after careful consideration, since overusing it can result in subject confusion and a dull tone. In general, subjects should act on their objects (active voice), not be acted on by their objects (passive voice). The subject should be the focus of the sentence, not the object.
Also, Jane Austen commonly used ‘they’ or ‘their’ to take the place of a singular antecedent, so the precedent for doing this is there. As a bonus, one needn’t say ‘one’ over and over in order to stay gender-neutral. The result, if someone uses ‘they’ or ‘their’ when referring to an unknown single person, is that redundancy is avoided. Compare these sentences:
1. “If one studies hard, then one should perform well.”
2. “If someone studies hard, they should perform well.”
Which one flows better?
Finally, I feel that professors that pull their hair out when they see a split infinitive are being too picky.