Pixelated brush strokes

Your wacom tablet should be using your regular brush settings. I have a couple of questions and ideas:

I wonder - is yours a regular tablet, or a Wacom Computer or Cintiq type display? If that's the case, you may be seeing pixelization on that monitor, but it might not show on regular monitors. 

If you're using a regular tablet, and you're using a regular round, hard brush, you may need to check your Flow and Smoothing settings. Also, try using the Brush Settings drop down menu ("hamburger" at the top right of your Brush Settings Panel) to "Clear Brush Controls".

Also, this can happen when you're working on a very low-rez document. What screen resolution are you using?

Hopefully, these ideas may help you determine where the issue lays. 

Let me move this to the Photoshop forum for you, where you are more likely to receive an answer to your question.

Note that the Community Help forum is for help in how to use the Adobe Communities. Product questions should be posted in the associated product community.