That first weekend after NYE will be more crowded than
the 10/11 - but much less crowded than 1st and 2nd.
Both places will be crowded on Saturday and less so on
Sunday. Since Universal is more manageable on crowded
days I suggest Universal on Saturday and Disney on Sunday.
To bad you can't move things by one day. Typically Disney
is very slow the Monday after the NYE weekend. And
Universal will be empty.