Little dictators that have too much prominence and visibility are the threats. If a specific start point gets too prominent a lot of users could be redirected from good instances because of the little tyrants that run such a jump on point. Granted it can be easily routes around by offering alternative entry points, but a certain amount of prominence will impact not so Tech savvy users.

And in your assumption you have shown you already understand the fediverse more than a lot of people ever will. They will just join an instance and browse /ALL.