I'd argue that much of D3's power comes not from the update pattern for DOM elements, but the reusable components pattern.

http://bost.ocks.org/mike/chart/

Examples in the core library, all compatible with Canvas, include scales, layouts, geographic projections, time/color utilities, CSV/TSV loading, and behaviors (drag/zoom/etc). There's some built-in canvas rendering like d3.geo.path which can be provided a canvas context.

The only things you lose are selections and the convenient transitions that go along with selections. But you can use these to modify and transition the canvas elements themselves!