"We might be better off .. finding ways to embrace failure, uncertainty, imperfection and insecurity instead."
I agree with this bit, because thats probably all we're going to get in the near future.
"The Greek and Roman Stoics, for example, argued that it was often wiser to visualise not the best-case scenario, but the worst."
But their mythology seems to contain a lot of murder and suicide?
"you should praise your children for the effort they put in, not for their achievements"
I think it is wiser to praise them on their progress - have they improved and achieved more/done better than before, or worse. This will help them self-direct their efforts effectively.