The problem isn't isolated to the altitude select knob, but also to the other knobs on the MCP and EFIS select panel, in the NGX's 3D cockpit.
Though the problem can be overcome by proper management of the flight, it is an absolute nuisance, particularly when wanting to set a Decision Altitude (Height) that is greater than a couple of hundred feet (refer to NZQN and LOWI charts for examples).
I know there are work arounds i.e. buying a more sophisticated mouse or by using a Radio Altitude DH, but these solutions are besides the actual point of the slow rate of numerical increment/decrement.
With that said, a fix would be desireable but not entirely essential.