I'll also add that the Brewers sure as heck rank their own when it comes time to offer up minor league talent in group tiers when targeting a major league player via trade. Most well known example was the CC Sabathia trade.
I can only speculate but if the Brewers were actively in trade discussions today with another team and offering up a package of minor leaguers, they'd have Chourio, Frelick, Mitchell, Turang, Wiemer, and Quero at minimum above Ruiz. And I think there's a good chance they'd have Black and Small above him as well. Reading between the lines it even sounds like Gasser was the priority guy between he and Ruiz in the Hader deal so I'd venture he's above Esteury too.
I think the dirty secret and most overlooked aspect of the Hader trade was that they had no intention of ever paying his final arbitration year, other teams realized it, and the prospect haul was going to be underwhelming at this point. Especially when taking back said trading partner's current major league closer (Rogers) as part of the deal.
Edit: And I think fans' expectations of this massive haul for Hader is directly leading to an overvaluation of the prospects received. It's hard for people to accept that the prospect return for Hader was 2 guys who weren't universally hailed as can't miss or near can't miss guys.