In case it's of marginal interest to anyone:

I've discovered that a number of the collects for Easter weekdays are not just new translations in the English 2010 ICEL Roman Missal, but are also new to the Latin 2002 Missale Romanum when compared to previous editions of the Missale and the Liturgia Horarum.

It seems that for a handful Easter weekdays (and one Sunday) the collects were duplicated from other days of the year, but are now given their own unique collects.

Here is what I've discovered:

2nd Week of Easter, Monday
was previously based on the 19th Week in Ordinary Time, but now has its own collect

2nd Week of Easter, Thursday
was previously the same as Monday of the Sixth Week of Easter, but now has its own collect

2nd Week of Easter, Friday
was previously the same as Wednesday of Holy Week, but now has its own collect

2nd Week of Easter, Saturday
was previously the same as the 23rd Week in Ordinary Time (and the Fifth Sunday of Easter), but now has two unqiue collects from which to choose

3rd Week of Easter, Monday
was previously the same as the 25th Week in Ordinary Time, but now has its own collect

4th Week of Easter, Monday
was previously the same as the 14th Week in Ordinary Time, but now has its own collect

4th Week of Easter, Saturday
now has a new collect because...

5th Sunday of Easter
was previously the same as the 23rd Week in Ordinary Time (and Saturday of the 2nd Week of Easter), but now has the collect that was previously assigned to Saturday of the 4th Week of Easter

5th Week of Easter, Monday
was previously the same as the 21st Week in Ordinary Time, but now has its own collect

6th Week of Easter, Tuesday
was previously the same as the Third Sunday of Easter, but now has its own collect

There is also a new collect provided for the Vigil Mass (and 1st Vepsers) of the Ascension, as well as an alternate collect for the Ascension itself.

While most of this work seems to be concentrated on Eastertide, there are a handful of other days in the Proper of Time that have had "touch-ups":

In Lent, there is an new alternate collect provided for Friday of the Fifth Week of Lent.

The "new" collect for the Vigil Mass (and 1st Vespers) of the Epiphany was formerly the collect for January 7/Monday after the Epiphany, which has now received a new collect.

The alternate collect for the Baptism of the Lord is duplicated from January 8/Tuesday after the Epiphany.