Wrath is not an essential trait of Gods eternal nature. In eternity past, before the entrance of sin into creation, God never exhibited wrath. However, in eternity past, God is love. Wrath is a temporary expression of Gods eternal nature of love because the goodness of His world and His image in this world has been temporarily compromised resulting in great havoc and injustice within His creation which was meant to reflect His goodness and love. But once God has finally destroyed all evil and redeemed creation through the slain Lamb, His wrath will be gone forever. This is why the Scriptures say "His wrath is but for a moment" and the most repeated phrase in the Scriptures is "His love endures forever." God does not just have love, but God is love itself. God has wrath, but God is not wrath itself.
The wrath of God is essentially negative in that the only reason it exists is because sin exists. If wrath was an essential trait to God's eternal nature, then that means for God to eternally exhibit this necessary aspect of His nature He would have to eternally create things that violate Him in order to be forever angry against them. This would mean that an aspect of God's eternal nature would rely on the existence of evil. For Calvinist Jonathan Edwards ("Sinners In The Hands Of An Angry God"), wrath was an essential part of God's eternal nature just as much as love, and this was precisely why God created the predestined damned who would be forever tormented under God's wrath in hell, so that God would have an outlet to eternally express His nature of wrath. But not only is this a horrifying idea, unsupported by Scripture (thankfully), but what did God do eternally before creating the predestined damned? Wrath must be a temporary negative expression (because of temporary sin) of His eternal positive nature of love.