I've never seen Walsh fight live. Just watching bits of his fight with Klimov, he appears to be a reasonably technically proficient southpaw. He hasn't really fought anyone all that close to the world level, but he's probably done enough to justify at step up to the world level and mandatory status.
As for Davis, he isn't some smoke and mirrors hype job. Pedraza is a decent fighter and much more proven than someone like Walsh and as soon as Davis really wanted to step it up and get him out of there, Davis did just that. Davis is probably worth the price of admission alone.