I think Thomsonfly may choose to serve Salzburg from NEMA, simply because nobody currently operates the route. It would probably operate as a 'W' rotation though I should think. I would be very surprised to see Thomsonfly opening a NEMA base in the future due to its proximity to Coventry. I recently spoke to part of Thomsonfly's commercial department and they seemed very happy with Coventry and gave absolutely no impression that they would want to transfer to NEMA, which is extremely cramped at busy periods (and hence would give Thomsonfly passengers a poor experience).
Thats my humble opinion anyway!