I'm with many others in not seeing why you regard "aware that XYZ" as equating to "acting rationally in light of the awareness that XYZ". This equation isn't true even for most human beings - why would it be true for an ooze?
On the issue of 'ooze knowledge', I think Ilmaro's hangup here is based on an overly pedantic interpretation of the rules. Lets examine this "you know all the effects on you" rule a bit more closely.
First as applied to PCs: There's no issue here. All PCs are presumably competent and aware enough that they reasonably can understand the implications of whatever they've been hit with. This is really what the rule was meant to address was players anyway. It prevents 'gotcha' ploys and cleanly prevents arguments about what the player knows vs what the PC knows in all of these, very frequent, situations. Given that the DM can create NPC/Monster/whatever powers and effects that break this rule if he feels it is necessary for story purposes there's no issue on this side of the screen.
Secondly as applied to DMs: Here we run into a terminological quandry faced by the writers of the game. They have 2 possible entities to which they can impute knowledge, the DM and the monster. If they say "the DM is aware of all..." that doesn't clarify the scope of his use of the information. Do all the creatures under the DM's control get to act on that information? Do any of them? Do none of them? By imputing the knowledge to the CREATURE OTOH the scope of the information is clear, the information is scoped to the creature. Given that the designers understand that the DM has the job of deciding what information to act on and DE FACTO knows everything mechanically going on in the game anyway all the rule does is define that other creatures don't know the effects and thus guides the DM to act accordingly.
Thus there is no issue with the rules and 'ooze knowledge'. The DM has information about effects and conditions related to powers used on the ooze, scoped to that particular ooze. He's still responsible for playing the ooze in character and deciding how, when, or if it makes use of this information.
As this applies to the "you can't charm someone without them knowing" thing... So what? That's the way magic works in the 4e universe. And again, ALL PCs are aware enough and competent enough that they will understand the ramifications, and again the DM is presumed to be playing monsters in character (or not, in which case who cares).
The whole issue is simply trivial and barely even worth noting.
This goes back to the "flag" issue. If it is just a flag, then why not just write it on the sheet? Unless you have some sort of resolution system for being a good musician, why is it important to spend PC-build resource points on it?
Or are you envisaging that the resolution system would be d20+skill and whoever gets the highest score gives the best performance? But this then gives rise to the question that Crazy Jerome in particular has talked about, namely, how are we going to cost that skill in a fantasy adventure game?
To come at the issue from a slightly different angle - the game has no "I'm a noble" skill. Yet presumably being a noble makes a difference in some challenges - everything else being equal, commoners may be more likely to listen to someone who instructs them to address him as Your Grace, for example. How would you handle this in a skill challenge? Perhaps grant a circumstance modifier to the Diplomacy check in question - +2 for an obsequious audience, -2 for rebels. Anyway, however you would take into account this non-mechanically represented element of the fiction in resolving the action, take a PC's background "skilled musician" into account in the same way.
Unforunately I can't XP these excellent posts.
Exactly, the player is perfectly free to define his character's background to include a talent at playing an instrument, weaving baskets underwater, etc. There aren't specific rules for how you might acquire these kinds of 'skills' because they simply aren't central to the theme of the game.
I'd go further, there is NEVER A REASON to have any sort of 'opposed check' in 4e. Consider, the PC vs an NPC is simply a DC set by the DM. It could be set via a fixed DC the DM invents or it could hypothetically be set via some arbitrary 'skill level' the DM sets for the NPC vs some 'skill' bonus possessed by the PC, which is exactly the same thing. Either way the player has to roll in excess of some number on the dice. Opposed checks are just pointless.
In the case of PC vs PC there's no conflict to be resolved. They are on the same side. The players decide which of the two characters they prefer to have 'win' the contest and that's the winner. They can fluff this as the better character won, or as the better character threw the contest, or whatever makes sense based on the choice they made. The outcome is in any case entirely under their control.
First a qualifier: I love 4th edition. It is currently my game of choice. I have tons of fun with it.
However...
One of the things that I don't like about 4th edition is the extremely light skill system. The skills are combat oriented, even the knowledge skills. I liked the non combat skills of 3e( i.e craft, profession, perform, etc.). I understand that background and DM fiat can grant me these skills, but it would be better if they were hardwired into the system rather than an afterthought. Like Dannyalcatraz said, I like to
know that I'm better than someone else rather than a random check or a "Yeah sure. You're better than NPC A".
I've actually thought about bringing over the 3e skill system to the next 4e game I run. I don't think it would be game breaking and might add some fun. (But that's a thread for the houserules forum

)
Yeah, except the issue with detailed skill systems is they don't work well at all. There are a dozen issues and they have all been beat to death in the past, but as a quick set of basic points:
1) Each skill you add tells the players what their characters CANNOT do, unless they have that skill.
2) Narrow skills simply mean that the party will most likely lack the key but unusual skill they need the one time per campaign they actually need it, thus narrow skills might as well not exist from the DM's perspective. He can't count on the party having them.
3) Which skill covers what? Is it mining, geology, or assaying that lets my character know how rich a gold vein this mine contains? The more skills you add, the more unclear it is what they actually cover and which one covers what.
4) The designers of games don't really know a lot about most areas of human activity. That is they lack most skills they will be designing and thus they will fill the game with misinformation more often than not. That might not matter to some people, but it will just irritate the people that DO understand that skill, which generally happens to be the people who care whether it is in the game or not...
Thus every detailed skill system provided in every RPG that has ever had one has broken itself on these same rocks. I am infinitely glad that 4e eschewed even the attempt and provided a nice set of general categories of things that characters would likely vary in their ability to carry out and just made a short fixed list. Sure, it can sometimes miss a few nuances (the guy that can climb but can't swim), but it also CAPTURES some that more detailed systems fail to capture, like the ability to fluff Perception to whatever sensory mode or techniques are appropriate to the character and the situation (the longtooth shifter smells the enemy, the keen-eyed elf sees them, etc).
And note that when a player is bothered by over generality they are quite free to restrict their character. If you don't want to know how to swim, just put it on your sheet. For that matter don't take Athletics training and instead grab a skill power that lets you jump really well or climb really well, now you've quite effectively differentiated without descending into the bog of needing 12 different athletically related skills.