It's weird mate,I genuinely think the biggest problem we've got with evaluation on our young players is the Rooney effect.
We brought through a generational talent, a complete prodigy of a player at 17 and lost him a year later, if you don't measure up to Rooney now you're written off, no end product - despite the fact his numbers compare favourably on his first season with sone of the best in the past 30 years (Ronaldo, Lampard, Gerrard, Giggs).
And if you look for signs of progression in a player - the signs are there already this season, last year he was either not getting in shooting positions or a ? x of missing the target or making the wrong choice. This season already hes shooting A LOT more and also hitting the target regularly, that's a clear sign of coaching and confidence having it's initial impact, I reckon it's only a matter of time till the next step on that curve us him starting to slot regularly.
Pretty sure Chelsea have broken down these stats too and see a clear trajectory of improving in an area he was lacking