What was so important about collective nouns? I dug out an old exam paper from around my 11+ time (1959, since you ask) and there it was. What is the collective noun for — and the list included starlings. It's a murmuration: which I did actually take the trouble to learn, and have never used since. Murmuration isn't even in my Concise Oxford. Collective nouns give doctors great fun. Periodically, the informal medical press or medical internet groups devise them for the specialties: a gasbag of anaesthetists, a stitch of surgeons, a fulfilment of GPs — that sort of thing.
Medicine has lots of words that mean extremely precise things, such as formication — a feeling of ants crawling over the skin, and the cerebellar sign dysdiadokokinesis. I suppose these words are necessary, conveying something that would otherwise be difficult to record and describe, especially if it needed repeating. Perhaps there is even a word for something that would otherwise be difficult to record and describe, especially if it needed repeating — please let me know if there is.
But some words are simply missing from the English language. If you have brothers and sisters, they are your siblings; your mother and father are your parents. But what about your aunts and uncles? Why isn't there a collective term for them? It would be quite useful in medicine as well as in everyday life. I'm sure geneticists, who spend a lot of time drawing those complicated diagrams with squares and circles on them, would welcome it. And what about a collective term for nephews and nieces? I don't know if these words exist in any other language, but whereas you can imagine less advanced societies getting on quite well without dysdiadokokinesis, all societies recognise human relationships. You'd think someone would have thought it a good idea to find a way of referring to aunts and uncles all at once.
The word sibling comes from Old English, and just means related by blood. I suggest taking the parental ‘p’ to replace the ‘s’, so aunts and uncles are ‘piblings’. Following the pattern, nephews and nieces become ‘niblings’, a nice word that describes what they do to their piblings' bank balances at Christmas and birthdays.
Another mystery is why piblings and niblings are differentiated by sex while cousins are not. In French they are cousins or cousines, but that's cheating.