If I may offer a western perspective (should I perhaps say 'EU'?)
'Trial approach' I am sure is a mis-translation. There is really no such thing (except perhaps in a training environment). Every approach, even in bad weather, is an approach to either land or go-round depending on what is seen at decision. A 'western' translation would be "we will have a go" or "we will attempt an approach".. Providing the weather is better than the minima (therein is a question?) it is legal and not unusual for pilots to make an approach EXPECTING to go-round.
ARRAKIS - "The more I go into the details, the more i understand how important was the readback by PIC to the ATC, especially given the weather conditions and the (in)accuracy of the system.
As there was no altitude readback by the crew, how should Smolensk ATC react? Go around?"
We still do not know what sort of approach was being flown by PAF101. I believe it was set up internally. ATC can do very little to prevent an approach and landing short of shooting down the a/c or positioning obstacles on the runway. It is important that some of you understand that there was no actual need for any readbacks for a successful approach and landing from what I have seen on the CVR.