I'm not able to zoom the shader editor canvas with my tablet (intuos4), only with the mousewheel. Would be grand if this would be possible in a future update.
Most of us here at the company prefer Blackmagic's Fusion's way of navigating in the node canvas by holding middle mouse and hovering over the tablet to pan and middle mouse + touching (left click) the tablet to zoom.
I guess Maya's alt + right click is fine too .
- Unreal Engine