What circumstances?  I suggest you ask Pope Francis.  I agree with everything else you say, just keep in mind that the Church is in the "already, but not yet" time window between the resurrection and the end times.  See Matthew 13:52 and "Depositum Fidei" 2.  Compare the 1994 catechism with older catechisms, and you may find some surprising discontinuities which, nevertheless, do not compromise perfect continuity with the Sacred Scriptures and Sacred Tradition.  For instance, go looking for the old stuff about women not being "proper matter" for the sacrament of Holy Orders.  Can you find it?  What else can you find instead?  Hint: CCC 1566