Well some more dh8-300's could be a good idea, im sure that in the long run it would be cheaper than having the atr on lease covering for planned aircraft downtime as well as the JS41 which is parked up at NQY at the moment and the odd JET2 733 when these too go tech!
Keep in mind that the birthday of SZ is coming up in October so perhaps something could be announced then, new aircraft and maybe new routes?
as far as jets go, i would expect to see props if anything at all, as surely it would work out more expensive having a mixed fleet ?