Yes and no. If your 4 spells would do equal parts of your damage and are up all the time, then yes. But f.e. the Big Dog and Fetishes deal way more damage than Garg and Haunt. But it is still better to mix elements than to go purely physical.
I haven't looked into it recently but I heard a while ago that the Sunwoko's set for monk was going to be changed so that the decoys always exploded with the damage type of your highest element% so you didn't have to always be holy.
Firstly, is this the case now?
And secondly, if this is the case then wouldn't that mean using this ring with sunwoko's would pretty much have you always benefit from a 200% damage boost?
There is an animation icon and a swirl around the toon that shows which element is buffed at the time.
I run it on my toon, Seasona. I love the ring as it allows me to teleport into a mob, deal arcane with the teleport, deal cold with my ice armor, deal lightning with my meteor and deal fire with explosive blast. All at once so one is buffed if I time it right (which isn't that hard).
Its very usable if you practice and get the timing down. Also, the icon works great for me. If you see the right dmg buffed you can often spam that dmg if you set up your spells right.
I originally didnt like this ring, but it works well, and it works great with Tals armor and the Halo of Arlyse ring, too.