Agree with Wazari, that gearing is a incredibly complex topic where you always make compromises. Last year gear ratios on 5 and 6 were a bit to short, I felt that the ratio between 6-7-8 could be made a bit shorter to remain in the optimal efficiency are of the engine. I would assume that while overall efficiency is very high, the area where the efficiency really peaks is actually not a very broad rpm band. Can you confirm that Wazari?
While for full high speed driving the gearing this year looks better, I do think that (for RB) this year, one can see two points where it's probably not optimal:
Low speed corners like found in Monaco. We are obviously operating on a grip limit, but having the engine in very low rpms basically forces the ECU to get more power out of the MGU-K and the MGU-H having to assist in order to keep the big turbo alive. (Btw, is efficient combustion possible in low load/pressure conditions? If would assume TJI works well, but the HCCI combustion happening at the outer cylinder walls will be instable or not possible at all - hurting efficiency) Also, much of regulation has to be done is order to keep torque steady since obviously we are talking about a transient system where boost building up can lead to sudden torque spikes (although the K probably acts as a "high frequency filter" while H and wastegate keep the turbo relatively stable.
The engine feels out of it's optimal rev range in low speed corners. A bit shorter ratios would make efficiency improve since more work can be done by the ICE directly.
Also, mid-speed corners seem to be a problem. I have a feeling, that the influence of the heavy chassis weight was maybe a bit underestimated, since the engines here really seem to struggle quite a bit some times. IMO it drains the battery too much.
But then again, everything is a compromise, and we don't know nearly enough to really say anything valuable here. My opinion would be that bigger ratios between gears 1-6 would help, but the gearing is probably just adapted to the concept of the car and to be honest. High speed cornering and straight line acceleration of the RB this year is very good. It has it's reason and one probably is the gear ratios selected.