I'm not sure Omicron has been with us long enough to assess the severity just yet, experts are saying two weeks more at least. By then the transmission will have passed to the more vulnerable. The other issue they are concerned about is the sheer number of potential hospitalisations, maybe not of the severity of previous strains but I'll enough to need hospital care. The mayor of London has just declared a "major incident" because of pressure on the hospital's, already.
Experience in South Africa is hopeful but their population differs greatly in age profile, natural immunity and vulnerability.