I'd agree with Area 51, more Italy, Rome especially, all the carriers are flying from Bournemouth to Spain/Portugal at the moment, probably because its a safe bet. Ryanair used to do Bergamo last year which is a handy place to start from in Italy, being central in the North.
Definitely more Eastern holiday destinations are required. such as Croatia/Bulgaria/Greece etc.
Thompson are doing Turkey and Sharm-el Sheik next year on their new 737-800, which will be nice!
On the domestic front surely Manx2, Eastern or Air Southwest could be lured into Bournemouth without upsetting Flybe too much? Such as to Blackpool or Liverpool etc thereby not competing with SOU-MAN route.