I've had the same issues, and wondered if it was something with my controls or the latest beta release(s). I have to basically hold full throttle (or close), pull back on the yoke, maybe tap each brake, to get the stock 172 rolling. Its very hard to control on the ground. :(
Running Windows 10, beta 13, saitek cessna proflight pedals, yoke, throttle quadrant/trim wheel.