Perhaps the wheels of God's throne are to indicate to us that God's throne is not staying in "Heaven" (which is actually where God's throne is)! Revelation 21-22 reveal that God's throne will MOVE - it will descend with the New Jerusalem to the (New) Earth after Jesus' Second Coming! God's ultimate plan is to join with His creation, creating Heaven on the New Earth, dwelling with us face-to-face forever, just as was the case before the Fall in Genesis 1-2.
God's ultimate plan is to bring the Heavenly and Earthly realms together in the resurrection and eternal Kingdom of God.
"And this is the plan: At the right time he will bring everything together under the authority of Christ—everything in heaven and on earth." - Ephesians 1:10 (NLT)
It is all thanks to Jesus' victory over sin and death on the cross, and His future victory in establishing the Kingdom of God in power and fullness as He vanquishes the evil worldwide empire of the AntiChrist. All glory to the lamb that was slain! The eternal dominion of the eternal Kingdom of God belongs to the Son of God and Son of Man, our amazing, loving, humble, just, and mighty savior! As the second/last Adam who fulfilled perfectly the will of the Father as a human (yet eternally was and is fully God, the Second Person of the Holy Trinity), He alone is worthy to fulfill the dominion mandate given by God to humanity, as the fully-God, fully-man, King of kings and Lord of lords.