If your playtime on chapter to is just under 2 hours couldn't you assume that the whole game is about 7 hours long? That may be short, but it's about the same as a COD game.
I'm waiting for a price cut for the same reason, but I don't think 6-7 hours is all that short. I just think that shorter games should cost less and they usualy drop in price pretty fast.
I felt the same way about Enslaved. I bought it day one and loved it. But if I had waited a few months I could have gotten it for a fraction of what I paid.
If 6-8 hours games were $30 and anything over 15 hours were $50-$60 I think people would be happy to buy short games on day one. Multiplayer can make a game more valuable, but games like MGR and Enslaved don't really make sense with a multiplayer mode. I say the price should reflect the content.