Note that there sadly also is a very strong effect that also can "ruin" (in principle) good redesigns for existing users: When all else fails (i.e. you are not able to guide your design by existing metaphors etc.), humans learn by repetition. That's why consistency with other products is usually not a bad idea: Search bars are usually to the top right, so when you put yours there, a new user will know where to look.
OTOH, this also means that for a user who has used your product for ten years, the fact that your search bar is, in fact, not in the top right, doesn't matter -- because they have learned where it is. If you move it, they will be upset, even if the new design might objectively be more intuitive (as in: new users have less trouble with it).
This effect can make it rather hard at times to judge if a redesign of a product you've used for a long time is in fact as bad as you believe it to be.