Indeed, making a new Force power makes your character strong, but for example, probably all of my Force-user characters have made a variation of an ability that already exists. Lilith's Dark Side Spell doesn't actually corrupt a person. It is more like a Mind Trick. Equa Dominator has made Talking Force thing, but it has almost no advantages. He still has to focus on the thing he is doing. And Jasmine... his ability will come soon, but it will be a variation.
Basically Star Wars canon has shown us so many powers that we could use. Different philosophies mean different powers, like @[member="Vulpesen"] said. I'll have to use one of my characters again, Ephyt-ri, to talk about that.

She basically knows nothing about the typical Force. She has learned using the Force to control nature and heal (in a bit different way). And Sorcery. Magic has been introduced to Star Wars with Dathomir. It is really different from the Force Jedi and Sith use.
If I had to make a new Force power, I would have to think for days. Everything is already made. I mean... everything that would be logical. Making a Force power to destroy a planet would be clearly too much because even Anakin and Yoda weren't able to do that. And they were probably the absolute limit of Force usage.