Have you turned up the TrackPoint sensitivity? The default settings are too slow and you have to push it too hard. Note that there are two settings in the Mouse control panel that affect it: the regular mouse sensitivity slider and a separate TrackPoint slider. I keep both of those turned up just a notch or two from the right (most sensitive) and also have "enhance pointer precision" on. With this sensitive response I've never had any RSI or fatigue from using the TrackPoint.

Something else to note here is a long-standing bug in the TrackPoint driver: unless this has been fixed recently, whenever the driver is updated it loses the TrackPoint-specific sensitivity setting. If you ever find the TrackPoint responding more slowly that it should after an update, double-check that setting.