Ah - sorry, it seemed like you were saying that WotC should ignore any and all such models when designing their rules.
And, while I agree that they shouldn't be the only method of testing and verification, they should be a large part of their testing procedure.
And, hopefully, they're putting...
I have to admit that this particular rulelet is, so far, one of my least favorite parts of the playtest rules.
I hate, hate, hate, HATE, HATE! fiddly little "this stacks, but this doesn't, except sometimes" exceptions on an item-by-item basis.
While the bonus type proliferation of 3E was not...
I'm pretty sure we already have that with the Healer specialty: 25gp per healing potion, can make 3 in an hour, and eventually they're maximized for free.
Amended:
The model tells us that when you're a fighter, facing melee opponents, using Parry or Protect is the best strategy.*
And, given the rules on Parry / Protect, it'll probably work on ranged opponents, too.
So, I don't think the test is quite as limited as you're proposing.
Moreover...
And yet, if the model is telling us that constantly reserving your Expertise Dice for Parry / Protect is far-and-away stronger than reasonably intelligent use of, say, Deadly Strike, then the model is providing a useful service.
Absolutely all of this.
I view identifying magic items by trial and error as a page from the same book that has "Standard Party Procedures When Encountering A Door." It was fun while I was writing it, the first time, but eventually it just gets old and formulaic.
At this point, it's very old...
No, it's absolutely fantastic advice, provided:
1) The rules aren't balanced with everything else.
2) The rules cannot easily be made balanced with everything else.
3) The rules, for some reason, need to be included to satisfy some particular desire.
If the rules have to be there, and they...
A. Men.
I have a really hard time with anyone who argues, seriously, that there should be less DMing advice and fewer DM tools in 5E, especially when the reasons given always work out to be so trivial.
Actually, it'd work great. I love swarm rules (and squad rules from SWSE).
I ran a rather large PCs-and-villagers combat against an invading Red Wizard with her apprentices and their human and undead soldiers using similar rules.
But, I posit, a "swarm of ogres" monster is not the same thing...