I think our other problem there is Mrazek plays very aggressively, and because of his size, so does Ned. The nice thing about Mrazek vs. McBackup is they have 2 polar opposite styles, and you can use that to your advantage depending on the team you play. BOS obviously owned Mrazek, but he was otherwise fairly solid in the playoffs. Mac is solid, but unspectacular, and won't make as many of those saves that require immense athleticism.
If you have Ned behind Mrazek, you have 2 guys who play very similarly, very aggressive, come out of the net, but very quick and athletic as well...does that begin to make us too predictable? One guy, when confident and playing with fire, can hang with the best goalies in the league, but when losing confidence, can struggle mightily. The other is a rookie, who will inevitably have up and down confidence issues and likely suffer a similar fate.