Would a modern HMS Unicorn concept make sense?

Would a modern version of HMS Unicorn be useful?

Yes, if the fleet operated enough aircraft to keep it useful; an LHD-like design would be the likely modern form.

The concept would remain useful if a fleet had enough aircraft to justify it. A modern successor could maintain and redistribute aircraft close to deployed carriers, although a small aviation inventory may leave a dedicated support ship underused. The likely design would resemble an LHD, combining aviation spaces with workshops and transport capacity. Fleet size and sustained maintenance demand would determine its value.