In 2010 the GOP only won 6 seats, and that was considered a "blowout". Six seats is the bare minimum to take the majority in 2014. They still didn't take the majority in 2010. In 2010 the GOP beat three incumbent democrats (the other three pickups were open seats). That was in a blowout year mind you, in 2014 you're expecting to beat three just to take the majority with 51 seats (not including John Walsh in this)...to go further then that you have to win in harder states that Obama won in 2012. In 2014 there is nowhere near as much momentum behind them and the polling shows close races for all the incumbents in competitive seats. Also this time there is the chance of pickups in Kentucky and Georgia. A blowout year "bigger" than 2010 (which is what's needed) is borderline impossible.