There are a number of issues that would need to be resolved before Solent could be considered as a viable airport for scheduled services.
Right now there are no navigation aids or IAPs. No runway or approach lighting. No Air Traffic Control, only an A/G radio service. No terminal. RFF only A1 with A2 on request.
No doubt in time all these issues could be addressed though at a cost. There is certainly development planned for Solent but it appears to be centred on g.a. I have seen nothing published that indicates development for potential airline operations (unless I am missing something), though one might have assumed the airline would have had some contact with the airport operator to discuss its plans.
Meanwhile it appears Air Alderney have taken delivery of their first aircraft with a second to follow shortly, as reported on the Aurigny thread.