Pros and cons of paragraph-based writing The ancient masters, such as Euler, wrote in a paragraph-based
  style, where each paragraph was numbered and tried to explain one
  concept in about paragraph-length.

Nowadays, papers seem more structured, with more headings, etc.

Is there any study as to the readability of both styles?1 

(I started writing a thesis which so far has emerged in
  paragraph-based style. This has worked pretty well for writing, yet
  readability might be an issue. Is writing like this a no-go?)



1 If not, how is your personal experience if you have written both ways?
Following the advice by @jakebeal, I am posting my comment as answer. 

Follow the norms of your discipline, if you want to be taken seriously. If everyone else uses sections and  subsections and you do not, it will only look bad on you.