This is a pretty exciting development. There are. of course, risks involved. But it is pretty obvious that the Brewers see Chourio as a franchise cornerstone, and perennial All-Star type player, and locking him up long term is indicative of the team's intention to remain competitive long-term, rather than look at a multi-year rebuild process.
Hiura was a solid prospect, But he isn't in the same stratosphere as Chourio. I don't know if the Brewers have ever had a prospect with the type of hype and tools this kid has. Weeks and Fielder were ranked pretty highly, but both had defensive warts that couldn't be overlooked. Surhoff maybe? Honestly, you probably have to go all the way back to Robin Yount in the early '70s to find a prospect that brings the same kind of total package Chourio has. This kid has superstar written all over him, and the fact that the team is looking to lock him up for a decade (or close to it) is huge.