TDD often makes your design better!
My point is that it can also make your design worse. Some TDD is better than no TDD, but no TDD is better than excessive TDD. TDD is a method you use in conjunction with other methods. Sometimes you’ll listen to the methods and they’ll give conflicting advice. Sometimes, TDD’s advice will be right and sometimes it will be wrong. Sometimes it’ll be so wrong that you shouldn’t use TDD in that circumstance.
It’s one of many tools you have at your disposal, but like any of them it’s not the panacea that solves all your problems.