I think you underestimate the power of the Ravnica duals (shocklands is fewer syllables, but Ravnica duals is so very specific that anyone who has ever seen them would know what you're talking about--it just seems natural, so that's what I'm going with for now). They aren't crappy knockoffs. They're by far the best manafixers since the Onslaught fetchlands. They make the Invasions CIP tapped lands look pathetic (and those things have seen quite a bit of use). They even make painlands look obsolete. Since they'll be legal in Standard and all that, they'll be in high demand. And they have value outside of Standard too, so people will be more willing to pay higher prices for them. The old duals have become ridiculously expensive, so these will be a more affordable option for many casual players, but I doubt they'll be $5 a piece. I'm no expert on card prices though, so I can't say for sure. I just think they'll be a lot more than $5.