I know the section well. It overlaps in content with a lot of other D&D writing from the period, by Pulsipher in White Dwarf for example.
But if that's your notion of sandbox play - so that any game mechanics that don't support that sort of play (in the sense that they push against it rather than render it optimal) don't support sandbox play - I think it's a little narrow. At a minimum I'd call that sort of play "dungeon sandbox + mercenary/tomb-looting motivations".
Well, they might not totally fail to support that, but their are games that would support it better. Similar to how I could use AD&D to create a fantasy/cyberpunk genre mix. But maybe it would be easier to play Shadowrun.
There is no reason, within this context, that smart play isn't taking a shot in the dark. What is not desireable is that the mechanics interfere with satisfying play, so that a player doesn't have to feel that he is making bad choices in order to have a satisfying experience.
This seems a good way to describe the idea, too.
An example for this I learned from people talking about their Call of Cthulhu preferences:
They noticed that eventually, they always decided to give every new character heavy weaponry, so that they have at least some survival chance against the horrors and cultits awaiting them.
But if you think about this - this is not really what you'd want from the game - the entire theme supposes that you are a more or less average human that gets dragged into cults and horrors, starting as an innocent investigator. Why should you then be loaded with automatic weapons, shotguns or elephant guns? But not having this kind of equipment is a bad choice for "smart play".
There could be metagame constraints that make it a less bad choice. Maybe characters get "survival points" at begin of play. Solving mysteries or uncovering evidence gets extra survival points. Starting play with a weapon costs survival points. Suddenly, smart play is figuring out the right ration of using (and having) weapons or solving the mysteries.
In Torg, the reality of Horrorsh was (as the name implies) a world of horrors. Werewolves and Vampires are waiting in the dark, and Spirits and other Undeads threaten you, as well as lunatic serial killers. The World Laws of Horrors required you (at least for sufficiently "special" monsters) to find a monsters "True Death". You could engage in as many combats as you'd liked, and used the heaviest weaponry available in the game, the only thing you got was a short reprieve (and spending a lot of possibilities). Smart play was figuring out all the clues for the "True Death" - and then you could beat the enemy once and for all. And this is exactly how you'd a horror game expect to work - you can't end the threat without investigating it. You might be able to shoot thousands of zombies in th mean while, but until you have figured out how to kill the mummified and reawakened Egyptian prince once and for, they keep coming.
Without the world law of the True Death, smart play would just be "business as usual" - shoot or stab your enemy until he doesn't move anymore. There is no point in spending resources or time on investigating. Mindless violence will do the trick every time.