I know stats don't tell you everything, but they do give the odd bit of interest. Anyway.
Player A Season 1 Games 21, Save% 0.896 GAA 3.64
Player A Season 2 Games 50, Save% 0.898 GAA 3.25
Gustavsson Season 1 Games 42, Save% 0.902 GAA 2.87
Gustavsson Season 2 Games 23, Save% 0.890 GAA 3.29
Similar number of games, not too dissimilar in stats. Gustavsson had 22 wins in 65 games. Player A had 17 wins in 71 games.
So I think it is still much too soon to write Gustavsson off.
For the record, Player A is Marc-Andre Fleury. The Penguins of then (2004/5/6) probably aren't too disimilar to the situation the Leafs are in now re long times out of the playoffs etc.