I mean, the panning was pretty impressive at the time as well. In Sutherland's 1994 "Bay Area Computer History Perspectives" talk https://www.youtube.com/watch?v=k_cevebLO-A&list=PLKTTWvMgeg... he points out flickering or 'jumping' due to the processor burden of rescaling in a number of places in the Sketchpad demo video, including at 42:30 https://www.youtube.com/watch?v=k_cevebLO-A&list=PLKTTWvMgeg... and at 50:10 https://www.youtube.com/watch?v=k_cevebLO-A&list=PLKTTWvMgeg... .