This thread should be framed by the context of athelets who have retired. The sophomoric fanboi bantering about Brazier, Sydney or any currently competing athlete (besides a Gwen who's fallen out) is stupid. Sure, they're all hyped, but some/most of them are earning/building the hype by improving.
If you look at athletes who have retired, you get to a measurable data set. I'll just do some Americans:
Lolo - overhyped yes, but like Gwen, really someone who is after headlines and attention, moreso than actual track fans thinking X is the next comeing of Y.
Meb - two great races amidst a relatively competitive (NATIONAL level) career. Sold for his name, just like Dean. Overhyped for the end of his career.
Webb - Overhyped from age 17, with hindsight being 20/20. Sure 3:53, sure 3:46, sure 1:43/27:30... but in between: what? A nice kick in paris, an 8th place on the world stage? I love and adored webb as much as anybody, but he never really delivered. He had the tools and showed the signs of being a great, but didn't deliver. Missing the mark of the hype/expectations isn't his fault, but he was overhyped. Still is.
German - See: Webb, sans real post-collegiate trajectory.
Ritz - i wouldn't say overhyped, overall. the hype was at a steady level from age 17 onward and he managed to continually surprise and compete all those years. He's got extra hype from the Big 3, dyestat fanbois, but when you step outside that realm, he's was mostly just a respected player, a la Kennedy, Jager, Sol, Teg, etc.
Pre - added hype because of his death, but he was competitive at a national and world level, much beyond say Webb or most other American distance runners of the last 20 years.