Freeze pane (from way back in WP)
Most won't be old enough to remember, but WordPerfect had an awesome feature, never imported into MSWord. Freeze Pane set the cursor in the middle of the visible space. When moving through a document, the cursor remained "frozen" while the document scrolled "behind." It meant no searching for the cursor when editing. Simple as this sounds, it made editing large documents WAY easier and more efficient.