I can't speak for melee equipment, but my recollection is that level-cap HQ equipment with similar stats will beat out level sync gear. For example, prism cape will be worse than black cape +1 under level sync.
You may want to make Spellcast adjustments for obvious things like gear that will lose all their usefulness because of the way level sync stats are dropped, but beyond that, I wouldn't worry about it unless you're doing a tough capped BC.
If you're still curious, don't forget that the level capped areas still exist for now.
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