Is Additional Fighting Style underpowered as the only class feature at a given level?

This question is inspired by considering minor homebrew improvements to the Champion subclass, which is frequently but not universally considered a weak subclass.

Looking at the class features, the following occurred to me about Additional Fighting Style (level 10):

  1. Most fighting styles don’t synergize. The main exception is taking both a defensive and offensive fighting style, leading to common recommendations of Defense as the go-to choice for level 10 Champions.
  2. Every class that gets a first fighting style gets additional features at that level (e.g. Spellcasting for level 2 Paladins and Rangers).

So Additional Fighting Style by itself seems pretty weak compared to the level 10 features of other fighter subclasses. Hence the question.