There is a big change, at least for me as a Druid player, that is coming in Legion. Specialization swapping on the fly is coming! I am not in the alpha, my comments are based around my own thoughts, understanding of the mechanics and various YouTube videos.
Specialization Swapping
Currently you have two specializations that you can swap between when out of combat. This allows greater freedom in play style and role for all classes, even pure dps classes. With this restriction dropped and the ability to chose any available spec, even greater freedom is granted.
Importantly for hybrid classes, like the Druid, all four roles can be filled when needed. Guardian for Tanking, Feral for Melee DPS, Balance for Ranged DPS and Restoration for Healing. This gives amazing flexibility when playing in all aspects of play. If the raiding trend continues where ranged DPS and Melee DPS numbers need to be balanced and some fights requiring greater healing capabilities, this is only going to benefit guilds trying to get the most out of their players.
Challenges
This presents a few challenges for all players that wish to utilise multiple specs. Managing multiple sets of gear, managing multiple artifact weapons and action bar layouts.
Applying a cost or cool down to swap between specs will be something that should be considered. The general consensus I’ve read from forums is that there really shouldn’t be a cost or cool down at all. Imposing a restriction will only reduce flexibility of groups and slow progression and gameplay. Something I hope/know Blizzard cares about.
The requirement to unlock a specs artifact creates a proving grounds style gear/skill wall to allowing secondary specs. The additional artifacts create even more of a timesink, requiring players to devote time to leveling multiple artifacts to be effective as well as time invested in figuring out the spec, I am looking at you balance!
Having multiple sets of gear is nothing new, but does require effort to manage and maintain. Tools like the inbuilt gear manager and AskMrRobot allow easy management, but will need to be updated to include multiple gearsets.
Although many action bar mods provide functionality to cover specialization swapping, expanding that to cover potentially four specs might be tricky to complete. Hopefully Blizzard decide to cover all the bases allowing an inbuilt system for each spec to have its own action bar setup.