New Numbers has no Auto-Complete?
Not right now, but the feature is coming back in a future release within the next six months. Apple has documented the missing features in iWork '13 in a new KB titled About the new iWork for Mac: Features and compatibility, where auto-complete for Numbers is listed as one of the features that will be re-introduced.

The new iWork applications—Pages, Numbers, and Keynote—were released for Mac on October 22nd. These applications were rewritten from the ground up to be fully 64-bit and to support a unified file format between OS X and iOS 7 versions, as well as iWork for iCloud beta.
These apps feature an all-new design with an intelligent format panel and many new features such as easy ways to share documents, Apple-designed styles for objects, interactive charts, new templates, and new animations in Keynote.
In rewriting these applications, some features from iWork ’09 were not available for the initial release. We plan to reintroduce some of these features in the next few releases and will continue to add brand new features on an ongoing basis.
Some features in upcoming releases in the next 6 months
Numbers

Customize toolbar
Improvements to zoom and window placement
Multi-column and range sort
Auto-complete text in cells
Page headers and footers
Improvements to AppleScript support

Last Modified: Nov 6, 2013