Hiya!
I actually LOL'ed at that.
Yeah, rereading my post.... I was a bit..."harsh". My only excuse is I'm going through a bunch of different new drugs and combos of them for my recently diagnosed fibromyalgia (at least that's what the Dr. is going with... still don't know exactly what's going on). Anyway, after a good sleep and no time for the drugs to kick in yet, I figured I'd post now.

I'll drug myself up after this post.
I should have probably rephrased as:
"I've played with people who learn the rules a certain way". I am also in a long-time group. I also have been playing since 1980. And, yeah, I too have most of my players from waaaaay back (15, 20 and even 30+ years with them)...and I
know we have our own hang-ups and "expectations of play".
I think that was what I was on about; the expectations of play part. In my game, I'd never allow the halfling-in-a-box thing to give all the bonuses to the halfling and all the penalties to the orog. It just doesn't make sense. I'd give the halfling disadvantage on his attacks if he wanted to avoid "bringing down" the illusion. If he didn't mind bringing it down, he could attack normally (not with advantage). I'd give the orog a penalty to hit the halfling equal to 3/4 cover, but weather he hits or misses, it will disable the illusion.
It's all about expectations of play and how we learned. From the sound of it, you and your group learned the "if it's in the rules, that's the way it is" type (which is what I meant in my original post...but with about 80% more snark...sorry!). I've played with people who also learned that way. Hell, I was even that way for a while...but then I discovered it didn't work for me and realized that the believably of the game (the "suspension of disbelief", as Gary mentioned in the 1e DMG) was much more important than always (or even almost always) deferring to the RAW.
I'm still standing by my interpretation of Polymorph and Illusory Reality, though. Polymorph, in my mind and in my game, is primarily a spell used to overcome unusual situations or deal with some situation that isn't combat. Turning into a fish to get through the underwater passageway, or turning into a hawk to scout the immediate surrounding or fly to a nearby tower top to deliver a message. Turning into a T-Rex to chew on someone...while fun...is probably a waste of a spell. This goes back to expectation of play. In my games, combats happen often. Probably more than 'normal' (a typical 5 hour play session of a dungeon bash will have roughly...10'ish... combats. During that time there will also be about 3 or 4 "danger" situations (poison gas in corridor, yellow mold covered room, extreme temperature, etc), and another 3 or 4 "hazards" (semi-collapsed corridor strewn with rubble, 80' sheer cliff faces down to a raging river, cave covered in 9" of bat guano, etc). Using a Polymorph spell for these situations would be a LOT better than turning into a big monster to kill something.
And the wall thing? I'ts 15' x21' (as someone posted above). That's not any where near "I win!". I can see my players using it to create more mundane items needed for exploring and surviving in the dungeon; a set of lockpicks, a crowbar, a water proof tarp, a canoe, a barrel and some oil to fill it, etc. As I said, using the wall as a "get the helloutta Dodge!" action when the chips are down and everyone's getting their butts handed to them....
that is a good use for it. Using it to try and 'control' enemies is useful for probably a round or two, tops. And now there's this great bloody wall in the middle of the cave that the bad guys can use as cover as well.
Anyway, sorry again for all the piss n' vinigar in that first post of mine.

I'll take my punishment now...
...
walks away to get a spoon for his specially flavoured corn flakes...
^_^
Paul L. Ming