Akilah

I think every language of sufficient complexity could be used to express ideas which are beyond everyday complexity and use of a language... but if a language included, as part of everyday usage, words which automatically express, clarify, or distinguish that extra complexity, then slightly more complex ideas are more straightforwardly communicable, and understandable.
Assuming all languages can express any idea with sufficient number of words and sentences,  then the economy of words and sentences with which a language can convey complex meaning is likely a good standard to judge languages, one against another.
 
That said, some conceptual conflations may be avoided if the language has inherently built in checks to avoid them.
I do not have any real world examples (I am no linguist) but I would assume if a language included modifiers to attach to nouns and such for everything previously experienced in reality, versus other modifiers to label nouns and such in connection with imagination or fiction or invention then that might be useful in orienting a mind toward distinguishing reality from fancy.
A language without the word form of "wish" (as a verb), as in mentally wishing something...  while doing nothing... might be equivalent to our lack of a common everyday single term designating something like: "casting a spell to do the impossible" or "using the force to move things" or "invoking a supernatural agency to effect some cause" (although "curse" or "bless" comes close to this last... two words I would also strike from the language if I could) ...  The term "wish" then might commonly be replaced with more sensible phrases (whose use causes some reflection regarding the validity of the sentiment): "if that were to happen it would make me happy", or "if I had the ability to somehow cause that to happen, I would act to do so", or "I really would prefer it if you would stop talking". or "I would be much happier if it were the case that reality was different from the way it actually is"
 
Again I have no real world examples, but since culture causes the evolution of language, a culture's philosophy and thinking inform and shape the commonly used words and phrases... so I would conjecture, a culture of rational thinkers would produce a better language.
 

The question of “best language” has plagued (pestered) linguists for decades, the question being a plague because there are so many different purposes that could be used as the standard for evaluating. Admirably, you specify a particular function – converting concepts into concretes (not e.g. “physical efficiency”, “popularity” and so on). I think it would be advisable to say what it means to evaluate a language as a means of concretizing concepts. However, I have to disagree with Rand’s statement that the function of language is expressing concepts: it is expressing concepts and propositions. We don’t just utter words – “horse”, “eat” – we utter propositions – “I need to borrow your horse so I can get something to eat at the store”. What would it mean for a language to be good for this purpose, or bad?
If it were completely impossible in some language to express certain propositions (including contradictions), that would be a “bad language”. But every human language has that capacity. Differences between languages are not in terms of what can be somehow expressed, but in terms of computational efficiency. As an example, in North Saami, there is a word gabba which in a single word refers to “an all-white reindeer”. That language has a concept that is lacking in English: we can express the same thing, but it requires a more complex propositional arrangement (not just white, not entirely white; that color is then attributed to “reindeer”). So where Saami has more vocabulary in a certain domain, we can call on the resources of language rules (and can express “all-white pig; all-white house; all-white horse” and so on in an analogous fashion, where Saami does not have specific words for these other all-white things). Of course they can use the same rule-based mechanism as we do for expressing thoughts about all-white horses; they just have some additional concepts, befitting their particular circumstances.
Languages do differ substantially in their systems of rules in a way that might seem to relate to “goodness”. In some languages, the rules for putting words together are very transparent, general and simple (Turkish is usually the example brought out to illustrate that point), and in other languages, the rules are very complex and item-specific – English is on that end of the spectrum of complexity. For example, you know what “up” means, but it doesn’t mean that in collocations like “look up”, “take up”, “mess up”, “give up”.
While English is more chaotic in this respect, we still can convey all possible concepts and propositions using the resources of English. It’s just that we have to call on a larger set of more specific rules to do that. There is no real cognitive downside to having more rules that are more specific compared to some other language, as long as there are, in fact, rules in the language. If every proposition required its own rules, that would be a bad language, because you can express an unlimited number of propositions, but you can’t learn an unlimited set of rules.
Back to my question: what does it mean for a language to be good or bad for the purpose of expressing propositions?

There's no mention of baseball either. Doesn't mean they don't care about it, it just means it's not relevant, beyond the painfully obvious: a rationally selfish person should take care of their health.
Rand smoked, and her body type didn't really allow her to appear thin, but she was not obese either. Clearly she paid attention to her diet. I would write off the smoking to the Oist tendency to be skeptical of popular and government advice...because such advice is usually wrong. So it took her longer to buy into it than most.
And her husband was thin through his life. So are all the men you mentioned. I doubt that's just by coincidence. No indication that they drink to excess or smoke, either. Clearly, they value their health more than the average North American.
I know most about Peikoff's habits, because I listened to his podcast. He is very careful to maintain his weight, at all times, and has been for decades. But he does so without the "nihilistic" approach of denying himself food he craves. He just has less of it, or switches off fattening foods for a few weeks, when he notices any weight gain.
P.S. But by all means, e-mail prominent Objectivists and ask. You'll probably get an answer from some of them. Or show up to an even they're speaking at, and ask. I'm sure you'll get the same answer back: health is obviously a value, and we should take care of our bodies.

What is health and how do you achieve it?  Reason supplies the answer
Why do you want to be healthy?  Purpose supplies the answer
Are you good at being healthy?  Yes?   Self esteem is the result
Now substitute wealth for health and ask the same three questions.
 

Humans notice causal chains when they're pretty young. This means, they start to figure out that when thing A happens followed by thing B, it is a common pattern, and if thing A happens followed by thing C it is probably coincidental. As they observe more closely, they start to understand the other elements in reality that are playing a role, and thus understand certain causal chains not just as "there's a pattern of correlation", but in a more detailed way: of seeing how that causal chain works and leads up to the observed effect.

This faculty is reason.