From a pilot's viewpoint when flying in Russia with imperial altimeters, I think the main issue is the workload issue in climb and descent. It seems that the sectors are not very deep, so you cross them very often in the climb or descent. As you hear in the video, a climb or desc clearance is given with often a freq change at the same time. The metric level has to be converted and confirmed by both crew before checking in with the next sector.
Reporting a passing level is tricky!
To get a continuous climb or descent it is useful to call approaching the level around 1000ft before. Then you will probably get transferred to another freq, check in and get further climb/descent. I got that tip from an Aeroflot Escort Navigator (Alexander) but it's useful to keep a modest rate of climb/descent.
Moscow App seem to be very helpful with weather avoidance. They have advised us of the position of CB's in the past and asked if we would like a heading change. This is before we had time to ask ourselves.
In the UK, if I am not very much mistaken, ATCO's generally filter out the weather from their displays. The info about CB's is sometimes passed to us but this is 'secondhand' based on pilot reports and/or their requests for Wx avoidance.
Good Video!
