There is the old saying 'if a job is worth doing, it's worth doing well'
Yes, but what is the job ?
The BBC have not set out to produce a complete instruction course in genealogy the primary purpose of the show/series is entertainment.
Have they done the job well ?
From my understanding much of what was shown was also coloured by Jane Horrocks own wish to concentrate upon the "strong women" (especially one).
Yes they make it all look easy
yes they leave a lot of uncovered territory
but we don't all want to 'buy the book' in order to get the full picture.

what would your reaction be if someone said "we don't all want to buy the certificates to get the full picture"
Personally I think the show succeeded in only ONE aspect "don't believe all family stories" but overall it was very similar to the first series and in consequence was very weak.