Guys, whats happening? help me!
Either this is a somewhat improbable coincidence or Jolla made a special feature to use the FP-Reader solely for convenience, as i kind of requested (at least i wrote about my usecase to not use the reader for security but for convenience only).
So, they touched the fingerprint reader inconvenience.
But instead of completely fixing the issue, they only slightly bettered the situation for users relying on the "security" aspect of FP-Unlock. For my (insecure) convenience, all is awesomely perfect right now.
Let me explain:

The issue was one having to press the power-button first to bring up lockscreen, then lift up the finger and tab/hold it again on the sensor to have it read and unlock.
Jollas "solution", introduce mce-tool setting that does not need the button to be pressed to activate the scanner/lockscreen but "only" tab on the sensor, then lift up and (~ONE SECOND LATER, when the lockscreen has fully loaded) tab again.
So when using a pin code, not much has changed as you still have a two tap process, now with much longer wait between the actions instead of the need to actually click the first time.
Spiiroin hints in the tjc thread it might be a limitation in Xperia X hardware and not be solveable into a on action process with jollas means(?).

Now, i do not know if jolla has planned the following, but if you have registered fingerprints and activate the mce-tools setting above but disable pin code in settings, there is my requested feature to unlock to homescreen/last app by simply touching the sensor once, bypassing the lockscreen

Could somebody confirm?
Is it only my phone that entered this state?
1. register a fingerprint in settings (if not done)
2. mcetool --set-fingerprint-wakeup-mode=always (or =proximity)
3. deactivate unlock pincode (if not already)
4. check if phone fully unlocks by only touching the sensor (still not reliable regarding pressure and targeting and works best without case attached tho)
Thx