I think by desolving the factions or having them be at peace we would remove those kinds of storylines.
Ultimately this is WoW, and maybe we have the next 2 expansions with the factions at uneasy peace but eventually Blizzard will want to create those storylines again, especially if there is ever a world revamp.
It's cool for the faction war to stay the subplot like it's always been (maybe took a more major plot in BfA), but I'd like the continued faction conflicts to stay happening in the background.