perspective
If there was no strife then we would all already be in heaven.
The problem with heaven and perfection is if that is all you've ever known, you take if for granted. Like a child born in wealth who is given his every whim and knows nothing else, grows disenchanted because it's all meaningless and empty to him. Until he experiences hardships he has no appreciation for his wealth. Until he suffers with others he seeks only to please himself. Until someone gives him without him being able to repay that person back - ever, he knows only money as having worth.
In heaven there is only God's will. On Earth there is man's will. Once we experience what a mess, and what a triumph that man's will can be, we can gladly submit to ourselves to God's perfect will in heaven that allows all to triumph in Him, through Him, not one over the other as we have it here.