On the topic. What is happening with mercedes, as I see it from lots of onboards. The problem is not the engine, I think and clearly not the air resistance, actually it should be less for mecr due to less frontal area that generates the drag (thanks to sidepods). 

The problem however is clear. The car generates such an amount of downforce that the suspension cannot keep up and start to lower the car to the level where the floor stops to work and throws the chassis up. If on straight it is not so critical, in corners it is a disaster. In high and mid speed corners that causes instability and additional stress in tyres. To lower this effect the team has to stregthen the suspension on compression and lighten on decompression, which in vice versa causes the excessive tyre wear during the corner exits (especially from low speed corners) and oversteer. 

I think, such a team as mercedes will work out the problem, they need 2-3 races more. Currently I dont think that the scale of problem is so critical that they have to develop the car from zero.

On ferrari - too early to say that they will be dominant. Their weakness - comparably high drag, their speed traps are not the best. Maybe they will be strong on high DF circuits, but on high speed tracks... we have to see.