I think many here have covered the basics.
Saying "no insta kill spells" is sorta silly if you can "insta kill" with a sword crit.
What it seems to be leaning towards is you can't "insta kill" or crit someone in the first round anymore due to the condition track thingamagigee and all the air bags, anti lock breaks and safety features. (Read as action points, "fate" points, "hero" points and not having to roll saves) and other junk that lets you avoid a deadly action against your character and by some virtue an NPC.
In other words the Dev's would seem to want to give the BBG just as much chance of surviving the first round off a miffed Initiative roll as the PCs have on every single round. Or... the dev's never thought of that and all this added hoo haa is what we call in art class "A happy accident".
More or less they want every combat to last longer than 1 round, and if we use the "Delve or "Devel" if you prefer" format and all the stuff these same developers have been hinting at for the last several years...no longer than 6. 1-3 rounds of paring down the condition of a foe, and "insta kill" once the condition reaches the bottom rung. By the 6th round the battle is over, everyone grabs a "power up" orb or token that sprouts from the corpses of the enemies and its quickly on to the next encounter that is sliding scaled for characters of 1-10, 11-20 or 21-30.
Of course we will have to have a long look at the rules when they come out to know if you could for example write a spell that automatically drops characters to the bottom of the condition track or not... or put some "oldschool" on classic spells to avoid the condition track alltogether.
Either way im startin to get a very strong "New Coke" vs. "Coke Classic" vibe here.
Since a MM2, DMG2, and PHB2 are already slated for release in 09... 08's "new coke" may very well turn out to be "09's Coke Classic."
Case