The 1552 prayer book was more reformed than that of 1559 and 1662. Now some changes were helpful; the 1662 book included, for the first time, an order for the baptism of adults (those of riper years) due to the influence of anabaptism and due to the need to baptise indigenous americans. However, other changes were unhelpful. Let me give two examples.
In the 1552 order, note the following: the words of distribution are only:
Take and eat this in in remembrance that Christ died for thee, and feed on him in thy heart by faith, with thanksgiving
and Drink this in remembrance that Christ’s blood was shed for thee, and be thankful.’ Cranmer removed the words he had used in the 1549 book:
‘The body of Christ which was given for thee/ the blood of Christ which was shed for thee preserve thy body and soul unto everlasting life.’
. Cranmer realised that some read into these words transubstantiation, hence their removal. His new wording was far clearer.
Now in 1559 both these clauses were joined together and used, a departure from 1552. the 1662 followed this practice.
Note also that, at the end of the prayer of consecration in 1552, there is no ‘amen’: the first amen after this prayer is at the end of the Lord’s prayer, the response to having shared in the Lord’s Supper. However, by 1662 the ‘amen’ was at the end of the prayer of consecration, which subtly changed the theology of Cranmer. For Cranmer, the emphasis was never on the prayer of consecration, but receiving the Lord’s Supper, and then in reponse praying and giving thanks to God our Father.
Now the 1662 prayer book is still reformed, and a very good standard of doctrine for the Anglican denomination, but it is simply not true to say that the changes made after 1552 are minor. In fact, as the examples I have cited I hope demonstrate, the changes were theologically driven and sometimes unhelpfully so.