So, you want to be a GM. These are the tough questions GMs have to decide. Oh, and by the way, you will be graded on hindsight. I am guessing the owner of said team would probably be against locking into a $100M contract for a 'potential powderkeg.' Investing $100M is some serious coin. I am guessing the GM doesn't really care abouit the money but cares more about the 2 first round picks and how to fit it in the cap. You also have to factor in the risk of injury when you have so many eggs in one basket.
If I were GM, I would be exploring my options right now, working on contingency plans. Which FA WRs will likely be available? Mike Wallace, Maclin, Andre Johnson, Cobb, et al.? And how much do they want? If some team offers Dez $15M/yr for 7 years with $50M guaranteed, I'd consider taking the two 1st round picks and signing maybe Wallace and Andre Johnson or Maclin or some combination of the WR FAs available and use the money saved for other value FA pickups available.