Probably more than a few attorney have thought the same way - just change "estate planning" to whatever.
If you are thinking about doing your own estate planning documents -- think about this, are you already an expert in a certain area that you would be aghast if someone were to take on your skill themselves?
Say, are you a professional hair colorist? A skilled musical instrument repair person? A certified public accountant? The hair colorist, instrument repair person and CPA would all say you would be crazy to do your own hair color, fix your horn and file an estate tax return.
As an estate planning attorney, I say that it would not be wise for you to do your own estate planning.
I do suggest reading the rest of What Lawyers Offer - Education, Experience and Knowledge. It makes excellent points specifically about estate planning but more generally about what you get from a lawyer.