Windows Phone Tango might intro a new chassis, phones with the Apollo update to appear in Q4
He mentions that phones with Apollo are not likely to come before Q4 of this year, with current expectations for it to be ready mid-June. That could be too late, considering that Apollo is said to introduce multicore chipsets and HD screens support - things that come standard now in all high-end Androids.
As for the Tango update, which will allow Windows Phone to be run on lower screen resolutions and sub-1GHz processors, he thinks it will be meant for a separate breed of WP handsets with different chassis. This might introduce fragmentation in the so far coherent world of Windows Phone, but not if such handsets are almost exclusively geared towards emerging markets.
Another interesting part is the confirmation that the Nokia Lumia 900 and the HTC Titan 2 were outed with LTE connectivity and the HTC handset with whopping 16MP camera because support for those features has been lying dormant in the current Mango version, while it was previously thought that these will be introduced at CES with the Tango update.