I think there will be some time changes and a few new routes as two aircraft still don't seem quite fully utilised. I doubt there would be an expansion so big for the need of three more aircraft to serve on top of the current two and all those flights operated by non-based aircraft.
I wouldn't be surpised to see an expansion of something like 300,000 passengers, you know, the usual type of expansion size with a series of 5 or 6 new routes (probably most likely including Greece I would imagine) and perhaps a 3rd aircraft, maybe four after a bit of schedule changing, but I really doubt there will be five.
I think the most likely reason, like I said in the Ryanair forum, is that because more aircraft are going to East Midlands and Manchester, they are taking some out of Bristol so that they are not adding any "new" aircraft and jobs to the UK market since it doesn't really support their claims of how damaging APD is the the UK.