Diablo 4 Season 15's Leoric's Crown can roll an affix that makes you even stronger
The Gem Power affix exists, and it can turn your Soul Splinters into a serious power boost.
A particularly useful 
Leoric's Crown roll has been discovered in Diablo 4, and it could make the new Legacy Unique helmet even stronger.
Leoric's Crown can roll the Gem Power affix that increases the strength of gems and other gem-like effects socketed into the item. Since the helmet can also hold Soul Splinters, getting this affix can give you a really big boost to the power of the Splinters you have equipped.
The problem is obviously that getting the roll means you have to fight the RNG boss first.
Leoric's Crown Can Roll Gem Power
As shared by Rob, Leoric's Crown has a chance to roll the Gem Power affix normally found on jewelry. This increases the strength of the gems socketed into the item, and it is particularly interesting for the new helmet because Leoric's Crown is treated as jewelry and can hold Soul Splinters.
Rob2628@rob2628𝕏You can get Gem Power in your Leorics Crown then Masterwork it improve your socketed Splinter for some crazy power gain in #DiabloIV!
Just tons of RNG tough 😁
That means a well-rolled Crown can effectively make the Splinters you socket into it stronger.
Exactly how much of a boost you can get depends on the Gem Power roll, so this is not as simple as finding any Leoric's Crown and calling it a day. You will want to look for the right affix and, ideally, a strong roll.
Be Ready for a Lot of RNG
There is one fairly significant problem, and it is the fact that getting the right Leoric's Crown seems to be very problematic.
Rob did not give an exact number of attempts needed to find the roll, but described the process as involving a lot of RNG. So if you are planning to hunt for the perfect Crown, you might want to stock up on the materials first.
And maybe clear your schedule. You could be enchanting for a while...
Still, if you are already investing in Soul Splinters, the possibility of boosting their strength makes this a particularly interesting item and affix to hunt for. The helmet is not just giving you somewhere to put your Splinters, but the right affix can make those slots considerably more valuable.