How will this impact situations where we want to come aid friends or guild members on a different layer?
A lot of the most fun and memorable world PvP encounters happen organically this way with both factions calling to arms in LFG, Trade, Guild Chat, etc. and having people log in, fly over, and brawl
At least with the current system we can dynamically group up or down and most of the time get people into the same layer, but if now we have to deal with even more complications with layer cooldowns, zone limits, etc. that sounds absolutely awful
If we want more world PvP with less ways to avoid it, the ideal solution as others have mentioned would be NO layers, not increasingly complex layering mechanics