I have a rare illness and I am doing medical research for it. Is this a good hook for university applications?
That’s not a hook. That’s a source for an essay. A hook is an URM, First Gen College Student, or recruited athlete.
I’m not sure if that’s a hook.
I know overcoming an illness may be “overcoming an obstacle”. I would think it would have to be a life-threatening illness, then.
Legacy is also a hook. When people say hook they don’t just mean something that helps make an application stronger. They mean a particular status or characteristic, usually one you have no control over (recruited athlete being the partial exception) that serves as a thumb on the scale. Colleges want people who fall into those particular categories and may relax the standards a bit, within limits, to admit them.