At this point we don't know if he is being replaced, and I'm sure a lot of people would prefer it if he wasn't replaced, but others, including myself, think there is room for improvement in the sound of the band if they bring in the right replacement.
Either way, it doesn't hurt to discuss it. Who would you want to join the band?
A couple of names I've seen discussed on the forums so far are:
Lindsey Stirling -
https://www.youtube.com/watch?v=6Q9hOTEPRxs
Allie Kral -
https://www.youtube.com/watch?v=LFMQQ8RPiPo
Sara Watkins -
https://www.youtube.com/watch?v=6gi8au3_BnM
Miranda Mulholland -
https://www.youtube.com/watch?v=Y7p89XbkMwU
Edit: And obviously, Jimmy DeMartini -
https://www.youtube.com/watch?v=Z6-QlKRTcU8