I promise I have no connection to Josh McCown or his immediate family (although I am pretty well acquainted with his mom).
In my mind, the expectations for draft picks are staggered by where their taken...
Round 1
Picks 1-20: Automatic Starter. Drafted to be a game-breaker, but needs to make a contribution in Week 1. Notable exceptions are at WR, maybe CB.
Picks 21-32: Anywhere from an immediate starter to situational player, but needs to contribute in his rookie season, but allows for adjustment to the pro game (i.e. Napoleon Harris).
Rounds 2-4: Very similar to late first-round picks, only less so. They'll be expected to contribute in their rookie season, but mainly in special teams and to spell starters or in junk time or starting due to injury. These prospects are expected to develop into starters before the end of their contracts, and should be starters no later than year 3.
Rounds 5-7: Mostly practice squaders and players that you might want to take a "flier" on, like WRs who are fast, but run bad routes and mediocre hands, or QBs from tiny schools but have nice intangibles. Low-risk picks.
You can't draft the same positions high every single year, especially in positions that are generally full-time, like QB, RB, C, MLB, and the two S positions. You have to give the mid-rounders time to develop, and the space to do so. There are only so many practice snaps, and there are only so many starter snaps.
McCown should be given another season to develop. He deserves that from where we took him. To take a QB in rounds one or two does a major disservice to our previous draft, to our defense-oriented coach (who can't continue to "coach up" bad players for 16-game stretches), and a team that's going to have a bad O anyhow.
I just keep reposting the thread because I think that people are wasting their breath when they talk about taking Leftwich. McCown may not end up being the next QB of the future, but the Cards are best served waiting another season to find out. Also, remember last season, when people were saying that Harrington might fall out of the Top 10 because there weren't any teams there that need a QB? He was taken, what, #4? Perhaps the same thing'll happen with Leftwich, and the Bears end up taking him.