What's the counter? Seriously. How do you counter this spell? Ward against it? Now every single important character must have a spellcaster to ward him at all times against this tactic. By its very nature, the tactic calls for an absurdly high-magic setting.
Welcome to mid-high level D&D. Glad you could join us. We'll be serving punch from an extradimensional space.
You ward against it by using the same high-level magic your enemies are using: antimagic fields, illusions, mind blanks, etc. If you don't use it, it's like refusing to use a gun against people armed with heavy artillery: you will be crushed by superior technology.
Yes, that's limiting. Yes, it demands a certain style. No, that style should not be invalidated by 4e. Yes, 4e should allow people to go around that style more easily than they can now.
The magic system was invented for a GAME. The spells have limitations (or don't) based on their assumed use in the game. If WotC had foreseen the Scry-Buff-Teleport combo, they would have written the spells differently. The players are trying to use loopholes in the game rules to circumvent the story. That's metagaming.
The characters are making descisions based on what the characters are aware of. Bill the Wizard knows he can use his crystal ball to see things, use his teleport spell to go there, and use his arcane knowledge of the body and soul of creatures to prepare them for battle.
That's making an in-character decision. JUST LIKE spending 10 gp on a longsword is a decision made by the characters who are aware of what a longsword can do.
Your argument that "the characters are aware of the reality" is like trying to rationalize the D&D wealth-by-level rules to create a functioning economy. It's like PCs deliberately taking a 200 foot fall or going swimming in lava because they technically, by the RAW, have the hit point reserve to survive. At that point, they're metagaming a loophole in the game rules. In my opinion, it's the same with this spell combo.
It's not metagaming. The fighter who can swim in lava has survived the full brunt of a dragon's wrath and emerged okay. They also know the dragon's wrath is more potent than any inert puddle of melted rock. They take a look at that pool, knowing the things that have happened to them, and they know "I think I can swim that..."
It's not using any out-of-character knowledge or game rules knowledge. It's knowledge based on the nature of the universe the character inhabits.
I'm convinced that the teleport spell was intended as a travel spell to allow high-level PCs to circumvent boring treks through the wilderness - not as a "drop in your assault team on the bad guy" spell. I submit that if WotC had conceived of this problem in advance, they would have written some of the spells differently. And if it's being used that way, then one or more of the spells in question probably need to be rewritten to disable that functionality.
(As an aside, per-encounter balancing by itself goes a long way towards fixing this problem - since the PCs have no ability to "go nova" in an encounter).
I'm sure atomic energy was intended as a cheap, easily available fuel source, an alternate to oil - not as a "blow up Japan" bomb. I submit that if the scientists who unlocked Atomic energy had conceived of this problem in advance, they would have never published their findings. And if it's being used that way, then the science probably needs to be covered up to disable it's functionality.
None of that requires me to have any "outside knowledge." Intentions, whatever. That has been the way the fantasy world has worked, and that should continue to be a valid strategy in the next fantasy world (though I would not regret it if it was a LESS advantageous strategy).
Sorry, but that's one of the most ridiculous things I've ever heard.
It's in fact so ridiculous that I can't take it seriously. Anybody who brings this attitude to a game is basing their character's perception of in-game reality on the fact that they (the players) are playing a game.
That IS metagaming, pure and simple. And if you won't take my word for it, I'll borrow a definition:
It's not knowledge of mathematical character statistics. It's the fighter going "Hmm...the Terrasque stomped on my head and I'm pretty okay, still....yeah, I might be able to survive a dip in the lava!"
The character himself, comparing his own experiences, knows his tolerance for difficulty (and knows that it has only increased as he has endured more).
It's okay if you're not comfortable with that level of power in the game, but it's blatantly false to call it "metagame."