Having done some more reading up, it seems that the Dagger and A-4C and Q variants aren't going to be included at this stage but there's still a possibility of them making an appearance.
Aerosoft plan to release the sim in 3 stages. The first will be ground attack oriented and feature the Harrier GR.3 and the Pucará, and the second will be air combat oriented and feature the Sea Harrier and Mirage. Both will be downloadable and cost €27.95 and €17.95 respectively, and you'll need the first one in order to use the second. The final release will be available as a download and as a boxed version, and include the A-4B and Super Etendard, plus all the additional assets in the first two releases. Price will be €39.95 for download and boxed versions, or, if you have the first two releases, €17.95 to update them to final release status.
Purchasing the individual downloads would total €63.85. Apparently there'll be no discount on the third one if you buy the first two. I'm leaning more towards the option of buying the final version at this point in time.
I think this probably reflects the niche status of flight simulation nowadays. I can see how this release and pricing model would be beneficial to the developers though, because user feedback and funds would hopefully drive development and produce a more polished final product.