With all due respect to Howard, I can't see how he can be worth of that contract.
All true, and i'm sure Orlando has thought that too. The problem is the contract spans 5-6 years for the better players and so the price must be appropriate to how good the player will be in the future, not the present.
If Orlando (or any team) takes a more cautious approach, say they'll offer $10M for Dwight, Dwight's agent will sign a 2-3 year contract or opt out clauses that can limit it to 2-3 years.
Then what happens is if the player does end up being good, they can opt out of your team. This is what happened w/ Rashard, Sonics were cautious and signed him to a lower contract so he included an opt out clause, and he's taking it. Now Rashard is a SF so Sonics will probably only a pay a few million more for him, but with Dwight in 3 years could command a huge paycheck.
Plus, if Orlando loses both Shaq AND Dwight Howard to free agency someone will probably be beheaded, so i'm sure they'll pay any money to extend Dwight to max length.