I feel like there are so many mixed messages about this, so I'm curious what y'all think. Do you think it's wise to email potential faculty in clinical PhD programs prior to applying? Why or why not?
The most important question you need to ask them is whether they are accepting students that year.
If they are, you could ask if you could come visit their lab
or you could tell them briefly about why you would be a good fit for their lab.
This is part of their job and it is to their benefit to have good students in their lab.
This. There is another thread on the main page about this topic and this is the general consensusIf you have a genuine question to ask (e.g., if it's unclear on their website whether they're accepting students or what their research interests are), I say go for it. But if it's just to ask a cursory question or two and mention that you're planning on applying to work with them, I'd say no; your time would probably be better spent elsewhere.