I am not sure it is meant to be competing with the .375H&H mag. I thought the 9.3x64 did that. I looked the cartridge up on Sako's web page. In terms of energy level, it appears to be a .358 Norma mag come .338 Win Mag that will work in a standard 30-06 length action.

Since it is a 9.3x62 +4mm - that is the case is the same onle 4mm longer, you can use a standard long action. I am guessing, but I think it was developed to get a bit more velocity out of the 9.3x62, making it more useful ? / attractive to modern shooters.

Your guess is as good as mine. The 9.3x62 has been, and still is, a very fine cartridge which just gets the job done.