If you could change one thing in the HP storyline what would you change

[Olorin]

I can agree with you and wasn't saying you weren't a fan unlike some of these people. I'm thinking they didn't use them because maybe they were new or they only members of the unspeakables could use them or something

It's a plot hole, as simple as that, there are a few

Why didn't Fred and George see Peter with Ron on the Marauder's Map?
Why don't people use owls to locate people? owls always find everyone
Why didn't Crouch Jr (as Moody) Transfigure Harry and simply bring him to Voldemkrt?
Why didn't the ministry ban a word sonthey could locate and catch death eaters (like the word "Voldemort" in book 7)
...