Of course there can be other issues, like the realtor "helpfully" setting up the appraisal with their own company, the one that just happens not to notice any major issues with the sale.
I also think that the convention of the the realtor taking a percentage of the sale as their commission is problematic as it incentivizes them to show you the most expensive houses instead of the ones that are best for you. I'd be happier if they charged a flat fee or a flat hourly rate.