Yeah, traction is an issue on a steep climb. When you're tilted back, the weight shifts to the rear wheel (which is doing nothing except holding your butt off the ground). The front wheel becomes unweighted. You lose traction and the front wheel can spin on a steep hill. Then you're walking.
This is unfortunately inherent to FWD, and is the major weakness of the design. Other really good things balance that for me, but it's there.
We have hills around here (seattle) that I can't climb, especially in the rain (we have rain!) or with a bit of sand or gravel.