I only had like five Dragon types across around 30 playthroughs (and one of them was Duralodon which isn't weak to anything Dragons are weak to)
It's my least used type, due to many of them being legendaries/pseudo-legendaries with super high stats but that usually become available too late, grow too slow, and sometimes can't actually reach their final evolution or learn their best moves before the Elite Four. So, Fairy type didn't hurt my team build, if anything it's the added weakness to Fighting and Dark types that caused me more trouble.
I think Fairy was a good addition, and the type chart is better balanced with it (although I believe it could have been better). The idea that "Dragons are the strongest Pokémon" was ok for the first or first two gens, but that gets old quick, and it wasn't good as battling other players became a more prevalent aspect in the games. They still do have the strongest stats overall, but they have one more weakness (and the fact that Dragon is an awful type offensively) to balance things out. Honestly I prefer Dragon being a type just like all the others.