Anglicization has always been about either preserving the meaning or the pronunciation of the word in a way where a native speaker of English can read and/or understand it, and Worcester's explanation as to how proper names are Anglicized feature the desire to make pronunciation easier as the names are not easily pronounced otherwise without knowledge of the language. Anglicization makes the word or name English.

It's interesting that two of your examples, Livy and Pliny the Elder, received their first English translations by the same translator, Philemon Holland. In the preface of his translation of Pliny, he sort of explains the basis of his translation, if not the particular reason as to why that specific form of the name (he spells it Plinie). As his original preface is pretty hard to real for the modern reader, the Critical Introduction to it may be easier to digest. It's a bit off topic as to your specific question but it does go into a fair amount about early modern translations generally.