It's like President Nelson saw my post!I've served in a number of elders quorum presidencies over the course of my adulthood and I have to agree with jamison. If elders were consistently men from 18 to 45 say and high priests consistently 45 and up (or whatever age ranges you wish to use), it would make some sense. The elders would be the ones responsible for service projects (wood cutting, yard work, snow shoveling, etc.) and the older high priests would do whatever it is high priests do (don't know as I am an elder). In our ward, however, we have elders who are in their late 50s (one I believe is pushing 60) and we have high priests as young as 28 because they were called into bishoprics during their student ward days. It makes for a mish mash of types in the quorums and means that the young high priests are never asked to do anything physically rigorous when it comes to service projects and the older elders may feel compelled to participate in activities they are not suited for.
Let's add one more fact. In our ward (and I think this is church policy but I'm not sure) high priests hometeach the single sisters (young and old). One rationale would be that a 70 year old brother is less likely to develop an inappropriate relationship with a 30 year old single mother. But what if a significant number of high priests are in their 30s?
And let's not forget that status within the ward is inextricably tied up with the priesthood you possess. The idea that it is "all the same priesthood" is cold comfort for some 65 year old elder trying to fit in with a bunch of 20 something and 30 something elders still wrestling with babies or a 30 year old high priest attempting to find something in common with men in their 60s and 70s. I know their are doctrinal reasons for the separation but I sometimes wonder if some of these policies shouldn't be viewed with a more practical eye.

The only downside is that now I will have to listen to the inevitable enthusiastic discussions/testimonies/commentaries in my ward about how this is an important revelation and that this is irrefutable evidence that we are a Church of guided by God, etc. etc. etc. Okay, maybe it is that but it seems just as likely to me to be the result of some careful reasoning and observation by the upper echelons of the LDS Church. Dramatic announcements are not automatically revelations.
But revelation or no, its a good, sensible change.