I think I would give New ICEL B+++ for its rendering of Gloria in excelsis Deo. Its advantages over the version which Old ICEL cobbled together, and which is now embedded in the Church of England's Common Worship, are considerable. It shares with Cranmer's translation the humility to translate what the Latin actually says, without conflating clauses in the foolish ('Enlightenment') game of avoiding repetitiousness. Old ICEL, to give but one example, reduced
'you take away the sins of the world, have mercy on us;
you take away the sins of the world, receive our prayer;
you are seated at the right hand of the Father, have mercy on us',
'you take away the sin of the world, have mercy on us;
you are seated at the right hand of the Father, receive our prayer',
as if every second of the time of everybody sitting in church is so ineffably (good word, that) valuable that they must be spared such redundancies. In fact, the whole hymnic style of the Gloria is based upon repetition and variation within repetition, as was so much classical poetry. (And Catherine Pickstock's wise words about Repetitions and Recommencements and the 'Oral' nature of Liturgy are relevant here.) New ICEL's version stands comparison with Cranmer's. If I were to criticise it, I would single out 'adore', which seems to me inferior to 'worship' because of the vibes the former has picked up in modern English ('Darling, I adore you' and 'I simply adore Chateau neuf du Pape'); I prefer 'God the Father Almighty' because the archaic postponement of the adjective, as in the Latin, enhances its audibility and status.
Notoriously, the traditional Anglican rendering of the second line of the Gloria is based on a different text of Luke 2:14. Cranmer tried to be Clever and Up-to-date here. The Latin text of the Gloria was based on the Vulgate New Testament; Cranmer, in the interests of scholarly accuracy (and probably also of Protestant Bibliolatry) based his version on the Greek NT. In the Latin Vulgate, 'goodwill' is genitive: 'peace among people of goodwill'. In the Greek, it is nominative: 'peace, goodwill among people'. But there's an amusing twist to this. Those Greek manuscripts which give the nominative are numerous, but are mostly later than another group of Greek manuscripts (not well-known in the 16th century) ... which give the genitive! Presumably it was from such manuscripts that S Jerome composed his Vulgate. The balance of opinion among Textual Critics is to think Jerome and the Latin Mass are right to read eudokias (genitive) rather than eudokia (nominative). I suspect there's a sermon here on the dangers of being a cleverclogs who brandishes 'the latest scholarly views' in such a way as to sneer at those more cautious. In my second curacy I had an incumbent who later became a Liberal Archdeacon, who often told us that 'Most Modern Theologians believe XYZ'. It usually transpired, on enquiry, that what he really meant was 'I'm almost sure that I read XYZ somewhere in John Robinson's Honest to God'.