This is a really interesting one - the more I get into Lean the more I realise my 'old way' of designing (almost analogous to Waterfall) was wrong. We should definitely incorporate user feedback into the design process - I just worry that we don't get enough of a chance to build amazing experiences when we're rushing through the Build->Measure->Learn loop.
How does this affect you, & what size product/team are you on?
I feel it most when hacking & coding my own MVPs - there's so much to be done & so much to be learnt design often suffers — but I'm sure there's better insight than mine!.
[sorry for butchering the original tweet to fit inside the character limit Josh!]