The move toward Node as a platform will make things like cosmetic redesigns much easier to accomplish. I don't think many design firms could, or would want to, work within PayPal's older stack, which requires knowledge of not only Java but dozens of internal services.

Keep in mind that PayPal is a gut-wrenching edge case of internationalization and localization. If you're an Israeli person transferring Thai baht while you're in Chile, the website must account for that while respecting your user preferences and all local, national, and international law. It's a gross problem no matter how you handle it, and it utterly prevents drive-by redesigns.