SoJ would be a lot better, more interesting, and I think, not actually OP, if it worked in concert with CoE.
Look at an example of a class with 4 CoE elements, and a setup with 40% elemental:
Assume a “base” damage of 100.
In 12 of 16 seconds, you deal 12 * 100 * 1.4 = 1680 damage
and in 4 of 16 seconds, you deal 4 * 100 * 1.4 * 3 = 1680 damage
for 3360 damage total.
If SoJ worked with CoE, and you again had 40% elemental, for 3/4 of the time, the large bonus from CoE would actually be overwriting that 40%, i.e. your bonus would be at 200% for 12 seconds, and at 240% for the remaining 4 seconds.
In 12 of 16 seconds, you deal 12 * 100 * 3 = 3600 damage
and in 4 of 16 seconds, you deal 4 * 100 * 3.4 = 1360 damage
for 4960 damage total.
4960 / 3360 = 1.476, i.e. a 47.6% increase in damage.
Now, if you just had 0% elemental on gear, in 16 seconds you’d do 16 * 100 * 3 = 4800, only a bit over 3% less damage than you’d have with that 40% elemental on gear. So you’d probably be better off without those rolls at all. But, there’s nothing particularly game-breaking that you could take instead. What other roll are you going to take on your bracer? A little extra defense, probably. And on amulet, maybe damage range or AD… either of which is going to be, generally, less than a 10% dps gain. Not particularly OP.
And of course, you have to actually trade out another ring to equip SoJ. Because you’d obviously need to have CoE equipped as well to take advantage of this mechanic. So you could take both these rings as well as the EW set, but that means no super-defense ring like Band of Might, Elusive Ring, Halo of Karini, etc. You certainly couldn’t combine this combo with Focus and Restraint.
And lots of builds for different classes already have rings which generally add more offensive value than that 47.6% increase: Ring of Emptiness, Krysbin’s Sentence, Short Man’s Finger, and Circle of Nailuj’s Evol, to name just a few.
Just doesn’t seem that OP to me. As-is, I think this ring is just more scrap on the salvage pile.