Not necessarily my experience. I wrote (and I am writing) several academic documents with it. There are its quirks, of course, but with good classes such as memoir, I don't feel the need to do a lot more than basic customization in the preamble. Still is a good tool for me.
For me the memoir class made LaTeX worse. The titlesec package is more customizable, easier to use, and reduced the size of the preamble significantly.