Just to clarify, I’m certainly not saying you can’t be successful if you’re tall or short or whatever–far from it 
Like @bissou I’d like to see more variety in sizes/shapes though. Like a taller woman and a shorter man falling in love. Or a woman with frizzy hair and generous curves being the ingenue. A girl can dream…
@connections Juilliard can’t really be compared to other programs. Few of those accepted for Juilliard’s drama program are right out of high school so they would likely have experience in professional theatre.
6’7"?!?! Mercy. Way to go kids!
@HappyDancer98, I realize some are not right out of high school. OP was talking about “Tippy Top” programs and how much high experience played into later success:
As OP says, “Another debate that pops up frequently here on CC: a few of the student cast members - all freshmen to juniors - had previous film/video/TV credits listed and two freshmen already had equity cards and broadway experience. Is this perhaps evidence that “tippy top” programs get freshman classes made up of students who would “shine” no matter what program they were plopped into?”
I was bringing up Juilliard as one example of such a program in the context of the discussion.
I have a 5’9" 16 year old D who models and a curvy 5’2" 22 year old D (the MT girl about to graduate). Guess who is always mistaken for the “older sister?” 
YES for variety of shapes/sizes!!!
Yes @connections I understand. Juilliard is definitely at the tippy top and its graduates have a lot of stage credits and they seems to do very well booking/creating work after graduation. My point is it’s somewhat of an anomaly. I think most of those accepted into the Juilliard Drama program are not right out of high school and most accepted have professional stage experience prior to acceptance and some already have drama schooling under their belts. It’s a different animal than any of the other tippy top programs in the States. I can’t compare it to RADA or LAMDA, or any program outside of the U.S.
@beachymom true story on the 6’7" ish… Not a rabbit I pulled out of my hat. Both deserving for various reasons.
I don’t know to what extent if you are tall you better be REALLY tall is an advantage or not. I think it may be something that differentiates you from the normal applicant pool. These 6’7 ish lads I don’t know would have had the same success were they not that different.
But the OP also applies to the question of weight. Should you be slim and fit and if not, be REALLY heavy vs. somewhere in between? Hate to say it but my impression is that you need to avoid the middle to the extent you can. Which leave folks in the middle (particularly females) with a choice.
@halflokum, An actor my daughter knew - with top regional theatre awards - was advised by her agent to either 'gain 40 pounds or lose 20 pounds." I definitely think that in between is not as marketable.
@connections this is kind off topic and not meant to spark debate. Just an observation. I don’t think the college audition process is any easier for a 17 or 18 year that has their equity card that they might have received as a child actor. I think it might even be a little harder. As for height. I think it’s again a Chrystal ball. I saw a lot of smaller boys at a program and I thought my daughter would be good to go alas no. So you never reall know what vision a director or schoo is looking for.
I joke with my daughter that she should put 5’12" on her resume…
@bisouu - I said I was 5’12" for YEARS (loved to watch people’s faces as they figured it out)
I am so happy to learn that tall-ness is not an obstacle for young men. (My S is 6’ 1".) I’m sure there will be other obstacles.
@Ducky312, Sure, not sure what you’re referring to–I totally agree with you. I actually wrote about that earlier in a different thread. I thought the college auditioning process would be easier for my S, since he’d been auditioning professionally since he was around 12, but it was actually more stressful for him.
As far as height, we are always talking about averages, not exceptions. But definitely, if you take a look at the classes of each program, you will see that some have a uniform vision - there’s a certain ‘look’ - others clearly choose a range of ‘types’, and others don’t seem to do either. Again, this says nothing at all about the individual person auditioning for a program. There are always exceptions. I would never say to anyone, “X program doesn’t seem to have your look, so don’t audition.” Nor would I say, “X program has your look, so it’ll be a shoe-in.” Always remember that BFA programs all have low chances 
As far as professionally, for sure there are certain types that are more marketable at any given moment.That changes from season to season. That’s reality. This market changes also depending on your region. The NYC market is different from the LA market, for example.
But just because a certain type is more marketable doesn’t mean that you are guaranteed anything if you’re the type; and just because you’re a less marketable type, doesn’t mean you won’t soar to success. It’s key to know your type and to know how to market yourself best given the realities of the market.
@halflokum Love that! My son come from a long line of tree-like people. I’m 5’11", dad is 6’1", but grandfathers are 6’4" and 6’5". Props to the the non-average!!
I don’t think there is purposeful size discrimination. Theaters hire what they need for the show they are doing and of course this comes down to type. And the talent pool they are choosing from. If they have settled on a leading man who is 5’11", chances are they will look for a female counterpart who is somewhat shorter. If they cast the 6’7" fellow as the leading man, they very well could cast the 6’ female along with him. In that case the short girl would be at a disadvantage. It really just depends on the show and that particular dieector’s vision. I don’t think there is purposeful discrimination against any height or size. Reality is, just as there are more roles for men then women in theatre, there are more roles for “average” height people. Doesn’t mean there aren’t roles for those at either end of the spectrum. They just may be fewer in number. Talent can help overcome some of this. Kristin Chenoweth is only 4’11" (other short actresses include Celia Keenan Bolger, Elena Rogers and Helen Hayes) and Kate Shindle is 6’ (as are Jane Lynch, Brooke Shields, Geena Davis, Tilda Swinton and others). So no argument that it may be more difficult to be hired if you are at one end of the height spectrum or another - but there are many who have had successful careers in spite of their height.
I do think most schools are currently looking for diverse classes of students. I’m not aware of any schools that only accepts one type. As far as college auditions go I think you are at an advantage if you are talented and a unique type be it your height, weight or other characteristic. schools have their pick of average sizes and looks. But when they see someone unique with big talent, they really stand out.
I would like them to cast a woman who is taller than a man and not think twice about how it looks.
At least in film, the men can stand on a box. (paging Tom Cruise)
The list of famous screen and TV actors 5’ 6" or less is pretty impressive:
Al Pacino
Dustin Hoffman
Daniel Radcliffe
Nathan Lane
Emilio Estevez
Johnny Gelecki
Michael J. Fox
Joe Pesci
Richard Dreyfuss
Ben Stiller
Martin Sheen
Henry Winkler
Rick Moranis
Peter Falk
Seth Green
James Cagney
and more…
Willam Defoe is “officially” 5’ 10" but having stood next to him in an airport check-in line I can authoritatively say there is no way he is that tall. For a guy that frequently plays menacing evil villains, he is really small and slight-of-build.
I have zero knowledge but I have tended to assume that smaller, all over, works better for movies as you are blown up so big on the screen and that larger was better for stage to help stand out in all that space. No idea about TV:) It does not make sense when I think it logically through but that has just been the way I viewed stuff.
@EmsDad like your William Defoe story, “official height” is apparently open to convenient interpretation. I checked into a hotel in Mexico City right next to Arnold Schwartzeneggar and I don’t think he is much taller than I am (5’8"). Search on his height and it says 6’2". No way. Just no way.