Would a pair of larger Invincible-type carriers have been useful before the Queen Elizabeth class?
Short answerNot as useful as aviation-capable LHDs and a third Queen Elizabeth-class fleet carrier.
NotesBritain already had several Invincible-class and supporting aviation ships, so inserting another carrier type between them and Queen Elizabeth would add little. A better path would replace Fearless and Intrepid with aviation-capable LHDs and, above all, build a third Queen Elizabeth-class carrier named Ark Royal. Paying the industrial cost of roughly three and a half ships while accepting only two left the force unnecessarily brittle.