1. There are a TON of reasons why your performance may be impacted. Please submit a detailed bug report on this so we can look into it, including game logs! By submitting this info we can actually look into what is causing it.
2. We'd love to be on other platforms! One thing at a time, though. Let's perfect things on PC first.

Our QA department and development are looking in to a recent increase of performance-related complaints, seemingly tied to Shadows. It’s on our ‘critical’ to-do list. Sorry I can’t be of more help right now.