At last, after so many fw updates so far, here's an update with some obvious improvements.
The most important improvement I have noticed is a great power management. Now, battery drains much more slowly than before.
Another feature that impressed me is the addition of some more metrics in running activity. In particular, I found out that it now records the following: Vertical Oscillation, Vertical Ratio and Ground Contact Time.
What has not been fixed yet is the addition of pool lengths in Pool Swimming mode. The sensor continues to be extra sensitive that even a slight off-normal movement results in adding a whole pool length.
Let's hope for the best in the next update...