Paying a veteran backup 3m is worse than paying Kunitz 3.85m. Your starter makes 628k
The whole point of moving on from MAF is you have a younger, cheaper, better replacement and you allocate those funds to a Malkin winger. So it's addition by subtraction *squared
You couldn't be more wrong. Getting a very good backup if MAF is moved is going to be key. Murray has been very good for us. However in a league that is this conservative, there's no way that the Pens would go into next season with Murray and someone like Zatkoff as the backup. Spend 2-3m (or whatever) to get someone who's good and who if needed can handle 40+ games. Ideally they will not have to, but seeing how Murray was already showing fatigue by the 3rd round of the playoffs, getting a quality backup (aka expensive) is very important over the next couple seasons.
You dont' trade MAF for cap space. You trade him for assets. If you gain a minimal amount of cap space, great. But I'd move him for Lehtonen if Dallas was adding enough that it made sense.