It would be nice to have 1 or 2 down at SOU especially when you consider some of the longer routes the Q400's currently fly:
Avignon
Perpignan
Salzburg
Verona
All of which are 2hrs+ segments on the Q400.
And of course the E175's opens up the possibility of new routes:
Barcelona
Copenhagen
Stuttgart
Hamburg
Munich
Milan
Madrid
Warsaw
Toulouse
Mariselle
I should really say that all of the above are merely suggestions, with some being more likely/viable than others!