Well, they haven't wavered from their Q1 release date, even though the Tech Preview has slipped. Read into that what you will, but to me that signifies that the TP has perhaps become a little less important to them in terms of actually testing the software. They must be very confident that they've got the majority of bases covered on the V1.0 release through internal testing alone in order to stick to the full release date, which means that the TP then becomes a de facto 'Demo before the real Demo'. As such they want it to be as clean as possible, hence the extra wait.
^ The above is probably a good example of manufacturing nonsense in an information vacuum...
^ The above is probably a good example of manufacturing nonsense in an information vacuum...