I'm working on a video that will have hundreds of text layers when I'm done. Lets say next month I decide to change all the text colors to red from black? Is there a "style" I can apply? Or will I need to change each individually?

Where were the layers created?? If they're saved as separate .PSD files, you can do a "Batch Convert" within photoshop..
When you open up Premiere, all the files will update..

depending on how your comps are built, you could make a master comp of all text and use an HSL-style filter or colorize. That would be the quickest.

Big Help!!!