First, most of these redesigns are done in good fun, as a thought exercise for the designer. New thinking applied to familiar context.
But secondly, it's so important to understand that all brands and interfaces are ultimately judged by your customers, who have "no knowledge of [or patience for] the requirements, constraints, organisational politics." I've just heard that argument way too often used to prop up a poor design outcome. Good design remembers that the context of your product is in the hands of your consumer, not in the conference room of your headquarters.
If someone outside your company offers some free thoughts on your brand and identity, it's not a bad idea to look them over. They are relating to you as a customer. (And usually, a huge promoter.)