Yes, I'm adding support for arbitrary text-based formats, including LaTeX. So it will be possible to write LaTeX and see a live HMTL preview generated by Pandoc.

In principle, it should be possible to create a PDF preview with proper SyncTeX support for synchronizing LaTeX source and PDF preview locations, but that gets complicated when Pandoc+LaTeX generate the PDF. It may be best to leave LaTeX-PDF previews to dedicated LaTeX previewers that don't involve Pandoc.