This topic has come up here before. My $0.02 is that precisely defining the term "high academic" isn't possible, and isn't all that important. If I hear that a baseball player is targeting HA D3s, then I assume: a) he's somewhere between the 50th and 70th percentile among HS baseball players--good, but not someone who is getting interest from big D1 schools. And b) he's focused on using baseball to help him get into a good college (often one he might not get into otherwise). When someone tells me their kid has a 27 ACT and 3.7 and is looking at HA schools, I know he's not going to make the academic minimums at some schools, but can potentially play at a number of very good academic institutions. I'm not going to say "nope, that's not HA" (but if asked, I'm going to advise that Amherst and Swarthmore are probably out of reach). And when someone tells me their kid has a 97 mph fastball and a 30 ACT, I assume he's probably not looking at NESCAC schools (although maybe Vanderbilt or Stanford are in the mix), and that his test scores probably aren't the most important thing about his college application.
The percentage of applicants a school accepts gives you some useful information, but it's a very blunt instrument. Some schools try to play with those numbers (e.g., by not charging an application fee so they gets lots of applicants), and some places are great schools but not so well known or attract fewer applicants for other reasons. Colorado School of Mines, for example, is a terrific school that has an ACT mean of 31 and accepts over 50% of its applicants. (They are D2, I believe, but the point stands.)
I take the same position on D1s. There are some schools just about everyone would think of as HA, others that might cause disagreement. Some of those "obvious HAs" do hold athletes to very different standards than other students. (And those athletes may be smart kids who can thrive at the school. A non-athlete with a 27 ACT generally isn't getting a serious sniff from the Ivies unless his parents are major donors or he has some other hook, but he may do just fine once he enrolls.)
One other thing I'll add (that many of you on the board already know, but some may not): At top-tier schools, having a 99th percentile test score, a 4.0 GPA and ten AP courses doesn't guarantee anything--schools like Williams, UChicago, etc. could fill their classes several times over with those kids, and a lot of them get rejected. The process is a weird "black box"--a student who applies to 10 schools with similar admissions profiles may get into 10, or 5, or 1 (or none) of them, and it's almost impossible to predict ahead of time. That is the value of baseball at HA schools. If you get a coach's tip, then your odds go from 5% or 10% (or whatever) to essentially a sure thing. (And--if you make the team after you get to campus--you get to play baseball for a few more years, which is great,)