I'm also quite optimistic. This was a preseason test where McLaren suffered no reliability problem, had no real spins that I remember and the drivers did a bunch of laps each day. They weren't bothered pushing for qualy runs and focused on understanding the car, race pace and tires. All in all perfect preseason test for McLaren. This will pay off during the season with better understanding of the car and better in season development.
Pace wise I believe we are still in 4th place, Racing Point while they were showoffs don't seem to have a huge race pace advantage and even in single lap pace haven't set the world on fire when others tried for a fast lap as well. Sure, they may start the season a bit ahead but with further development they will fall back behind. There is a lot more in having a fast car than copying design of one. I do believe Mercedes made a big step forward, and will dominate the season. Bottas casually doing a 15.7 is proof of that. McLaren may have closed the gap to top 3 teams, but may end up further behind Mercedes than before. This could open up opportunities for McLaren, if Red Bull and Ferrari are lagging behind Mercedes they will be forced to adopt more risky strategies and engine modes. This could lead to more reliability issues for them so hopefully McLaren can be comfortably 4th to pick up the pieces.
Can't wait for Melbourne.
PS: McLaren is 3rd in number of laps, Mercedes 903, Ferrari 844, McLaren 802, Racing Point 782, Red Bull 780, Alpha Tauri 769,...