It used to be we had two groups:

Those who only cared about the text, and if there were tags at all, they could be visually interpreted any which way, since they were primarily there for indexing purposes or something;
Those who wanted to make their HTML look exactly like the mockup they made in Photoshop or Illustrator or Quark.
And today we’ve got just the one group, and their battle cry seems to be:

HTML must only be used for semantic markup, but that semantic markup must rigidly adhere to the pixel-accurate positioning in the spec, so that we can still design our web pages in Photoshop!

This is, of course, a complete about-face. It’s really quite bizarre. I must have slept through the point when the transition occurred. Either that or it happened in almost complete silence: I would have expected that kind of coup to have left behind rivers of blood and mountains of the dead.

In addition to making code reuse and code organization more difficult, we’ve found that classes can be a large barrier to learning React. You have to understand how this works in JavaScript, which is very different from how it works in most languages. You have to remember to bind the event handlers. Without unstable syntax proposals, the code is very verbose. People can understand props, state, and top-down data flow perfectly well but still struggle with classes. The distinction between function and class components in React and when to use each one leads to disagreements even between experienced React developers.