This is one of my thumbsticks, and the easiest to follow:
Again, it seems like a lot, but it does move pretty fluidly. And if you'd like, you can set the thumbstick (the small inner circle) at 0% opacity so it won't be seen.
There is a way to do this just with a touch input and without a thumbstick, but imo users tend to slide their thumb around the screen, which makes them have to stop, lift their thumb and bring it back down to the corner. This way it gives them a point of reference for their thumb.
Sorry to bump such an old post, but I've been using your method for a mobile game I'm working on, but the movement is a bit janky. There are brief moments when it seems to move properly, but usually the direction doesn't change if I am sliding the stick in different directions.