I know you're asking that question to point out what you consider to be obvious, but actually I would say the answer to the question is more "yes" than "no".<p>A redesign in this case may help get new users, but it's much easier (and more cost-effective) to retain existing customers than to gain new customers. So, if your change upsets existing users on any meaningful scale, then it's probably not a good idea.<p>I'm not saying to never redesign. I'm saying that you should redesign iteratively and in small steps, so that both existing <i>and</i> new users benefit. You never want to attempt gaining new users at the expense of existing users.