Why does his age have anything to do with this discussion? He is a better player than Marchment now, that's at least how i see it. He has one year left on his contract, so we don't need to do his projection or age curve. I don't get a notion why old players cannot be good now.
Other question is, do they need to acquire somebody at all? Theoretically they have Brandsegg-Nygard and Mazur who are not there yet. So there are three possibilities:
1. you spend a lot of capital to acquire somebody more aligned age wise (like Cuylle) and figure out what to do with MBN later
2. you spend less capital to solve the immediate issue short term (Lee, Marchand or Marchment) and still bet on MBN or Mazur being long-term solution
3. you just don't care about short-term issue and continue hording capital.
I don't see why option 2 is not a viable option as it improves roster and chances of making playoffs, while keeping long-term flexibility and cost low.