"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
MacWorld San Francisco Xserve, LCD, PowerMac Updates?
While Expos have become de-emphasized by Apple as venues for product releases, based on product timeframes a few Apple products do appear to be due for revision.
Apple's server solution, the Xserve, is stalled at Dual 1.33GHz G4s which were introduced in February 2003. While G5 Xserves updates were described as "imminent" by Appleinsider in October 2003, subsequent reports claimed that G5 Xserves were still months away. ThinkSecret adds that a 3U formfactor is under consideration for the new Xserves. No reports specifically place the Xserve at MacWorld SF, but G5 updates are long overdue.
After initial expectations of a 30" Apple LCD and redesigned screens, more recent rumors claim that LCD updates have been pushed later. Unconfirmed hints told to MacRumors, however, have suggested that Apple LCDs should see revisions at MacWorld SF.
Apple made a remarkable leap forward with the introduction of the 2.0GHz PowerMac G5 in June 2003. With it came promises of 3.0GHz PowerMacs within one year's time. Apple since made a surprise introduction in November of the Dual 1.8GHz PowerMac but left the high-end PowerMac untouched... leaving January updates unclear.
Most recent rumors, however, still suggest that PowerMacs will see updates in January, possibly bringing significant speed bumps.