Would you have given Alicorn the same advice if she asked for it before writing "Luminosity"?
Think that would have been a good move. Advice can be pretty good at presenting the outside view -- isn't as good at presenting the inside view unless the advice-giver really knows the advice-receiver well (ETA: meaning relevant details to receiver's specific case, etc.). Receiver should keep this in mind and update on relevant evidence (especially inside view evidence) that giver likely did not take into account.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.