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".
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.
I'm not saying to never redesign. I'm saying that you should redesign iteratively and in small steps, so that both existing and new users benefit. You never want to attempt gaining new users at the expense of existing users.
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.
I'm not saying to never redesign. I'm saying that you should redesign iteratively and in small steps, so that both existing and new users benefit. You never want to attempt gaining new users at the expense of existing users.