Fire on the Mountain

Is the God of the New Covenant a lot friendlier than the God of the Old Covenant? Conventional Christian teaching depicts the revelation of New Covenant in terms that contradict the image of a stern and fearsome God speaking from Mount Sinai. Was that the intention behind the comparison between Mount Sinai and Mount Zion in Hebrews 12?

For you have not come to what may be touched, a blazing fire and darkness and gloom and a tempest and the sound of a trumpet and a voice whose words made the hearers beg that no further messages be spoken to them ... but you have come to Mount Zion and to the city of the living God, the heavenly Jerusalem, and to innumerable angels in festal gathering, and to the assembly of the firstborn who are enrolled in heaven, and to God, the judge of all, and to the spirits of the righteous made perfect, and to Jesus, the mediator of a new covenant, and to the sprinkled blood that speaks a better word than the blood of Abel." (Hebrews 12:18-24)