A few of you asked for the option to clone an idea, so we've just shipped that.
The main scenario you described was that as you gather more insights into an idea, you're realizing that sometimes it's turning into something big that you want to break down into smaller chunks.
Jira Product Discovery doesn't yet let you create hierarchies for ideas yet (we're still thinking through the best way to do that, although in the meantime you can use the flexible fields and views system for scenarios like this) but with this change we think we saved you quite a few clicks: what you're able to do is copy an idea and remove the bits you don't need - instead of having to create new ideas manually, copy over parts of the description, copy over some of the insights and delivery tickets, etc. it's just one click.
Here's where you can find it: here:
We hope that helps!