I've got a standard arducopter quad frame with 880kv and 12x4.5 props
As soon as I arm the quad even at 10% throttle my quad wants to bank to the right.
I'm in stabilize mode, and I've tested the quad in my hand, it does what it should which is fights me trying to bank or pitch it.
I put full left trim and move the CoG left and I'm able to get the quad off the ground and hover it, but it takes a lot of left roll to keep it at the hover.
When I move the sticks when the quad is on the ground 10% throttle, when I move forward, left, or back the motors only make small changes to RPM but the quad not moving, but if I give it right, the left motor wants to flip the quad, even at such a low power setting.
I had similar issues last week. For me a big difference was re-calibrating the ESCs. I didn't think I would need to, they had been fine for a long time, but it made the difference.
Be very careful going too high if you are having to give more than a little stick input to keep it level. Ground effect makes it less than stable, but mostly in each direction, not just very strongly to one side.
Just my 2cents.
Try in flight balancing - arm for > 20 seconds, hover, land. Repeat until it goes up straight. This has helped mine tremendously, with low wind it hvers handsfree.