I could go on and on but from what I have seen GGG, the people of POE like to see variety.

Glacial hammer has a chance to cause a giant shard of ice to impact the target area (create an aoe effect for it). The most commonly used currency in Path of Exile is Chaos Orbs and Exalted Orbs. Due to this particular reason, orbs has been made into a reliable source of currency to trade, sell and buy items. Viper strike now applies crippling effect (reduces the enemies attack speed by 30%) or of that sort. Path of Exile doesn’t has an actual currency system For example, it doesn’t has any gold, money, in-game cash or any sort. Summon skeletons now summons skeleton archers. The same thing can be done for any of the other lackluster gems like summon skeletons. Or spectral throw now does not return but does the combined damage in 1 hit. A legendary that modified how the base skill worked. Say the spectral throw jewel now makes it so that you could only throw 1 projectile but it has a chance to spawn vaal spectral throw on hit? This is kind of like the way justice was changed for the crusader in D3. Now if this jewel provided some interesting mechanics or changed the way spectral throw worked, then I would definitely love to try it out. The spectral throw threshold jewel I find lackluster because it is just a damage boost for a huge sacrifice (the jewel socket). I love taking gems that nobody likes to use and making some crazy insane build with it. Heavy strike jewel - Double damage? Interesting concept - curious about reflect damage. Burning arrow jewel - love it - provides both utility and clear speed

Path of exile wiki threshold jewels