Absolutely necessary addition to CK2 and well-made as well, but charging £9.99 for it is simply ridiculous. Reformation of pagan religions a very good idea but it still lacks ability to create custom-made empires.
The Old Gods does just about everything you could ask for in a sandbox strategy game expansion, and with far fewer initial bugs and technical issues that any previous release of the series. [Aug 2013, p.75]
It would have been cool if every nation added in The Old Gods got the same detailed treatment as the ones from the Legacy of Rome expansion, but still, this is a fascinating journey into the unforgiving Dark Ages.