Teams also involve coaching, so let's not put the blame on a failed 2015 campaign squarely on the roster. Some aspects of our game improved, while others regressed, which was unfortunate but it's on to next year.
However, I mostly want to point out that virtually no team can build a whole roster of starters from drafting alone. Teams miss in all rounds through no real fault of their own. You can pretty much never count on a day 3 selection to be a long term answer to any need your team has. It is always a blessing if that happens. Whaley had a high grade on kujo and wisely added insurance with the Henderson pick. They both could have turned out better, but you can't blame Whaley for poor drafting there. Who else could he have gotten at the time that would have changed everything for us? As for Miller, give him another year.
I can't rant about every pick, I'm just saying teams probably hit on about half of their picks and they can't keep every one of them forever. And really, the only teams that can mask roster holes have stellar coaches and/or QBs.