I respectfully disagree with this line of thinking. I know a lot of people agree with you, I just think it's a half in, half out mentality. Murray helped them win a Cup and was usually fantastic. What more do we need to know? It's just weird to me to agree Murray is the guy but only so far as dumping MAF and overpaying a backup in case Murray isn't the guy. I don't get that philosophy.
I could see it if we got to round two or three, but I'm not sure what else there is to see at this point. Just get a regular ol' backup and save the money. If Murray falters a Reimer-esque guy isn't going to save us, and who's to say we couldn't trade for one during the season anyways?
Three things.
1) Murray played 21 games these playoffs - in which we generally made things extremely easy for him by limiting the shots he was facing. Not to take anything away from how well he played, but there's a big difference between playing 21 games while the team is rolling and playing 60 games over the course of 6 months.
2) It's called insurance. Murray is the future of this team. Yes we have Crosby, Malkin, Letang, Kessel and a great supporting cast. But one of the reasons things look so bright is because of how promising things are with Murray. But that doesn't mean we should just throw him to the wolves and let him sink or swim. What happens to him mentally and for his long term development if we sign a meh backup (someone who is good for 20 games, but won't push anyone to be a starter), and Murray falters/stumbles next season? The added pressure of having to be good/great every night, the expectations of fans for this team (largely intact) pushing to repeat? Look, I think he'll be fine. But for both his sake and the teams sake, getting an experienced backup and someone who could start 40+ games if needed should be an absolute must if (hopefully when) we trade Fleury. Reimer would be perfect (other than I think he'll get overpaid as a FA), but if he'd take a 2x3m deal I'd be all over that. I'm not looking for him to "save us" in the sense that he'll lead us to another cup. But I don't want to completely write off the season due to MM stumbling, and someone like Reimer is good enough that they can keep things going until MM hopefully finds his game.
3) Trading for a position of need mid season is expensive. Look around the league as of the TD last year. Other than Reimer or Ramo, who would have been available who you'd actually want? Howard, Lehtonen/Niemi? Maybe Lack. But it's a pretty short list. Add in salary/cap concerns, and making a deal like that can be tough. I'd much rather sort it out in June/July then hope that if something happens, we can magically fix it in January.