Item set bonuses are a great source of power in DDO which these days are almost mandatory to have if you want to be competent in high level content. I see an issue with one specific type of set bonuses, specifically the 3 item set bonuses.
All of these require an armor and two other types of equipment to get the bonuses. The problem here is that a player is forced into using these 3 items with no way of customizing the way they obtain the set bonuses. I have a proposal that may be able to circumvent this issue, exclusive set bonus jewels.
An exclusive set bonus jewel would allow for some gear build customization in that a player could assign an item outside the typical 3 items to provide part of the item set requirement. Making the jewel exclusive would mean that only one of these jewels, no matter what set bonus, could be placed into a jewel slot. It would also override any other set bonuses on the slotted item.
It's a small change that would have a big impact on what gear is accessible to a player's build. For example, if I want the Dreadkeeper set, but there's also some gloves that would fit my build better than the Dreadkeeper gloves, I could insert a Dreadkeeper jewel into a necklace that would allow the necklace to be part of the Dreadkeeper set requirement allowing me to use a different pair of gloves in my build.