I don't think a citizens assembly is a substitute for competent, democratic government, though. The recent one (100 people I think - much broader than the small citizens panel on the Covid response) came up with lots of nice sounding recommendations, which the government should take account of in the next Parliament. They aren't fully formed policies by any means, and much more work would need to be done to implement them. It takes up time, yes, but it's not like a full time job. I agree having to take time off work or arrange childcare to attend the sessions could well put off parents or carers - especially single parents, who may have to save all their leave to cover holidays/ child sickness or whatever. And unless it is a kind of jury service system, it would attract people who already have some kind of interest in politics - but that's the case already with local democracy (community councils, charity boards and so on attract "certain types" of people, which is why they are always trying to increase representation of women/ ethnic minorities/ people with disabilities and so on). So it's a good thing to do, but it's not really that earth-shattering an idea.
There would also have to be some kind of legislation as to how "bound" governments are by the decisions. Otherwise they could easily just not do anything towards certain recommendations if it's too difficult or expensive or unpopular. Or they could put unpopular/ controversial decisions to a panel or assembly and so pass the buck on actually reaching a decision (which the SNP does have form for doing in forms of public consultation exercises, which then get either shelved and never spoken of again, or used in a "numbers game" to support scientifically illiterate but publicly popular policies).
So while it's a good idea to increase public engagement and so on, I don't think it is safe to put "in the hands" of an otherwise incompetent administration - and it wouldn't let such an administration off the hook!