College baseball teams that aspire to compete consistently for their conference's title intentionally create competitive environments within their own rosters (and I wouldn't expect the Ivy League to be immune from this attribute). From the coaches' perspective, it's impossible to know which entering players will work out; so, it's inevitable that if they err, they err on the side of bringing in more players than their known level of openings requires.
I think the large majority of coaches try to restrict this practice to reasonable levels. However, because they're working with extremely imprecise estimates, they're going to fall prey occasionally to the charge that they've "over recruited" in a given year.
In the example here, Dartmouth's current class of 14 for 5 roster spots may seem excessive; but, the fact is that no one will really know for a couple of years. This season's roster could end up being somewhat heavy in underclass players; but, the combination of higher-than-normal losses of players and a smaller class next year could bring the mix back into alignment.
Because of this, I've found myself judging programs on a relative scale; hoping to see year-to-year adjustments made to keep proportions of players by class in some "normal" range and maintaining a willingness to give a coaching staff the benefit of the doubt when the roster becomes a little "freshman heavy." Programs that follow this pattern tend to have relatively few transfers out over time; something to follow by recruited players and their parents.
On the other end of the scale are those programs that consistently bring in large classes. Often, transfers make up between 1/4 and 1/2 of the entering class. In this environment, only elite freshmen play regularly. To make room for each year's large class, a steady stream of players transfer out; some at mid-year.
So, how does one know in advance where a program stands on the recruiting scale? Going back three-to-five years, I'd look at the following:
(1) Size of entering class. (Souce: News item on program's website)
(2) Percentage of transfers in each entering class. (Source: News item on program's website)
(3) Who played the most innings, transfers vs. freshmen/sophomores? (Source: Season statistics from program's website)
(4) How many transferred out? (Source: Archived rosters from program's website, if available. If not, you'll have to get a feel for this from discussions with current and past players and/or their parents.)
(5) What's it like to be a freshman there? (Source: Conversations with current and past players who arrived as freshmen and/or their parents.)