https://www.wowhead.com/news=316277/...-29-fire-mages
As long as we will have classes with high burst dps litreally incomparable to others - like nobody can't even hold a candle, we will never have decent balance.
And before you say it's irrelevant, it is relevant for everyone as high burst specs will be always more desirable than others.
Consistent damage is always less reliable as high burst shortens fights, makes some phases/adds last shorter amount of time and generally makes things easier.
Capping AOE won't prevent that... as long as blizzard continues to add ridiculous trinkets and other on use effects that can be stacked.