Two routes missing from that ideal lot, Milan 5-7 weekly E175 and Cork 4-7 weekly Q400 (More likely with Aer Lingus Regional is you ask me though)
However I think they would have to be added very slowly and even then I think we will have to wait until the economy picks up. The short Irish routes such as Derry, Knock and Shannon would also be best served by Q400's and I would also add that most routes would have to be built up to those sorts of frequency's and equipment as will the airport itself (Only stands 1-5 can handle E175's and 2-5 for E195's!) and I would imagine BAA would also have to find a way of making more space in the terminal, ideally with a couple more shops, as there's only 2 currently!!
I personally would like to see Flybe expand from SOU but at a slower rate than other and new airlines, thus reducing their dominance and also the airports dependability on them.