Definitely necessary. MRI has a visual/spatial resolution of about 10^-3 meters; microscopy has a resolution of about 10^-6. Its like the difference peering through the window of a bookstore vs being able to go inside and read.

In addition, depending on how you prepare the tissue, you can investigate the protein or genomic content of the neurons and learn about their functional properties (as well as their structure). Along with functional MRI, this technique is the bread-and-butter for learning about normal and abnormal brain function in humans.

I'd go farther and say that clear writing is especially desirable in academic papers. When you're trying to communicate complex, abstract ideas, why make the prose any more complex and abstract than it needs to be?

BrokenHalo makes a good point about Improving Our Word Power, but I think writers benefit less from a good vocabulary than they do from good editing skills -- and the willingness to rewrite, revise, and edit until their prose is crisp, clean, direct, and clear.