This whole price topic is odd. Back in the 8 and 16-bit days, a game of this size would cost the same as games that were infinitely bigger or with much larger teams. Why are people getting hung up on $5? Games costing different prices is a good thing, as far as I'm concerned. A standard $9.99 or $14.99 makes some games cost more than they should, or maybe less than what they're worth. This could easily be worth the $19.99.
Is it the quality of the game that is overpriced, or the game size? I think the problem lies in an absurd amount of money for a title in your example ($200 vs $500), whereas $5-10 won't break the bank for a good deal of people. I guess the problem lies in what people see as what is worth a dollar compared to someone else. For the cost of an IMAX movie, you're getting a game that's potentially 4-5 times longer than most IMAX movies. Just using this as an example, if it's a matter of you feeling this isn't a big enough game to warrant $20.
The other thing is, Saints Row: Gat out of Hell just came out, and it's $19.99. That game, according to most reviews, is two hours.