Probably not. And just so long as your monsters and NPCs act with the same lack of certainty, it's probably not a problem.
Indeed. Any enemy on my board with a low INT acts as such. Enemies will flee, surrender, or only defend themselves. My monsters are not simple EXP fodder that will always fight to the death. Suffice it to say that I love subjects like monster ecology and behavior, wherever I can find it.
Check out these two phrases from your post.
In the first, you describe an enemy being bloodied. In the second, you won't describe an enemy affected by "Charm Person". Isn't that a little dissonant? I can't help but notice one helps the monster, and one hurts the player; neither is good for the player.
As I said in my post, I'll only describe something as bloodied if I must and it's exceedingly apparent(perhaps down to 1/3 MAX HP, for example), and even then, I describe them as bloodied, not Bloodied, if you understand what I mean.
And I don't give a crap about the player. Unlike the 4E mindset, I'm not here to make the PCs look awesome or make it easy for them. I'm here to present a challenge through world-making, story, and roleplaying. My players can usually handle it. And when they can't, I'll lighten up on a CR, not my methods.
I have found (as player and as DM) that even if the DM obfuscates, eventually we learn "the code", and the obfuscation fails. So all that's really happening is you are punishing the players for not picking up on your code yet.
YMMV.
The moment I resort to OOC terminology in the name of convenience instead of clarity is the moment that immersion is broken, and just flat out lame if it gives my players an advantage. Sure, they're smart, and they can figure out my "code", but that doesn't mean I'll stop. Like a political spokesperson, I'll speak in thick code till the end.
Actually, in 3rd edition, a spellcaster was RAW aware of when his spells succeeded or failed, except when noted otherwise (certain divinations). If someone made a saving throw against your spell, you were aware of it, and could act accordingly.
You might be right, and if so, it's probably just something we bypassed. And even if we didn't bypass it, I would tell only the caster that it succeeded, and it would be up to his character to somehow convey it to the rest of the party. If they did it by shouting, I would have the remaining enemies act accordingly to the new information, assuming they had the INT to do so and could understand whatever language was used.
Bloodied is a visible condition, players should be told about it, and a lot of the game design is centered around the players knowing it.
Give me a break. Firstly, it's been well-established on this board and others that HP is not an abstraction of wounds, but of staying power. I could be playing a Swashbuckler whose HP represents his ability to dodge and parry attacks with great effort. As his HP dwindles, so does his strength and speed, and the final blow could be the one that connected, one that finally pushed his exhaustion to unconciousness.
And if you want HP to represent wounds a little more, that's fine. But you can't tell me that something begins bleeding at 1/2 max HP. I realize that Bloodied is important for some characters to know, and for that I'll perhaps have the Class in question make a Perception check with a circumstance bonus to recognize it.
If you couldn't tell yet, I'm a simulationist gamer and it's how I run things. I'm sorry if you don't like it, I was just trying to throw another opinion into the mix.