If the Cardinals are in position (and it looks like they will be) to take a franchise QB they MUST pull the trigger. By franchise QB I mean Luck, Mallett, or Locker. (This of course is assuming they don't pick up a big time FA in the off-season. That is not their m.o. and I don't believe they get that done.)
A team is rarely in position to take a franchise QB and must roll the dice if they are. Of the 32 teams in the NFL 17 of them start a 1st rounder and four start a QB taken no later than the early 2nd round.
Since 2000 26 QB's have been taken in the 1st round and 15 of them have been good to great. Three have been mediocre. Seven have been busts a la Leinart and one I give an incomplete grade (Tebow). Not one team that has had a chance twice in that decade at a franchise QB has completely whiffed both times. Just so you know, the guys I gave good to great grades to are: Pennington, Vick, Palmer, E. Manning, Rivers, Roethlisberger, Rodgers, Young, Cutler, Ryan, Flaco, Stafford (he's been injured a lot but looks good when he's in), Sanchez, Freeman, and Bradford.
Including the three moderates (Leftwich, Grossman, and Campbell) plus the incomplete (Tebow) in with the 15 good to greats, thats 18 qb's out of 26 that the Cards would be better off with than what they have now. Plus, those odds look pretty good to me.
I am aware that the Cardinals need some other positions very badly such as OLB and O-line. In fact the O-line must be addressed via draft, trade, or free-agency along with picking a franchise QB or else it will seriously stunt his growth. The Cards offensive line gave up 93 QB hits in 2009. That's incredible considering K. Warner had one of the quickest releases in the NFL.
The bottom line is that after a terrible year, a rebuilding must occur. Why not start that rebuilding with the most important player on the field?