i agree that more should go into how a player develops, we've seen some coaches turn around some pretty underwhelming players, but better scouting agencies in the game should still have an impact on the quality & accuracy of the talent reports u get - especially when it comes to sleepers.
keep in mind there are still brown players that didnt pan out on other teams as well. courtney brown & gerard warren for example. i guess with so many high draft picks they had to strike gold with at least one of them (edwards - even if his tenure at cle wasnt great).
the broncos drafting has been pretty poor in the latter shanahan years as well. they were great at getting RBs from outta no where, but there were so many misses in the first round. al wilson, dj williams, jay cutler & ryan clady were good, but jarvis moss, george foster, ashley lelie, willie middlebrooks, deltha oneal & marcus nash didnt really pan out. they didnt play that well on other teams either. oneal did okay for the bengals, but he started out as a RB in college and wasnt that great as a cover corner.
look at the lions history: mike williams, roy williams, charles rogers, kevin jones, stockar mcdougile & joey harrington. none have really made the impact that were expected of them. even on other teams (jury's still out on roy williams i guess).
the raiders are another example: russel, micheal huff (both those guys are still young tho), fabian washington, robert gallery, tyler brayton, phillip buchanon & janikowski. now he was a good kicker... but a first round for him?
compare this to teams with good front offices:
ravens: flacco, ngata, mark clayton, suggs, ed reed, todd heap & jamal lewis. the only misses in the last decade was travis taylor & kyle boller.
pats: mayo, merriweather (first few seasons werent great, but he's playing well so far), logan mankins, wilfork, bejnamin watson, ty warren, daniel graham, richard seymour.
chargers: cromartie, merriman, castillo, rivers, LT (this is during AJ Smiths tenure).
this is why i think scouting agencies should have an impact in game.