That's a good point. I think the author is merely stating how there is a "watering down" of the faith over the last 30 years, and the altering of the Act of Contrition is merely one sign of such watering down. I found the title of this work to be particularly intriguing (although it didn't turn out to be what I thought it would be about) because I've met some people online that actually deny that Hell exists. Apparently this is a common belief in some "Christian" sects, but I never knew that before. I found it rather distressing that a (relatively minor but still present) sign of such theological rejection may be creeping into the Catholic faith. (by omitting that part from the Act of Contrition). Call me paranoid, but I believe Satan works in subtle ways sometimes.
As far as the "perfect" vs "imperfect" contrition, you're right there's a difference and it's as you said, the perfect being because we love God, and the imperfect because we fear Him (or more preciesly Hell). However, whatever contrition is engaged, absolution is obtained in confession whether it's perfect or imperfect. The distinction is made (I believe) merely to point us in the right direction (which is love for God over all else) not really to put a gradient scale on confession or the type of absolution obtained.
(just making the point for the record, not that you were saying that)
I think I want you to write all my comments from now on. Nice and succinct.
"because of your just punishments, but most of all because..."