Jumping midair still works for Pyros, Jacks and probably others.
But it is much less useful now because engine change nerfed Newtons to the point that it is much harder now to build launcher with enough range.
With Spring 91.0 you could launch Roaches over whole Speedmetal with just 2 Newtons, while now with 2 newtons their range is only about 70% length of the map.
And yeah units stick to the ground much more. From my experiments, in order to launch the roach at all, you need to have it move towards the newtons on the ramp. In case it is not moving, Newtons will have no effect on it.