A fair question, one with lots of answers. While only someone like Metzen would be able to give you the definitive reply, I'd say that the Scourge have picked up control over frost abilities from their stay in Northrend. It's pretty hard not to realize how awesome throwing snow and ice is when you live with it year round.
An argument could also be made that because Ner'zhul was a shaman prior to becoming the first Lich King, he transferred some of his shaman abilities (which include control over frost) to the Scourge.
"When Cataclysm arrives, I know Shadowfang Keep and Deadmines will be reworked as heroics. But what will happen to their original forms? Will SFK still be available for pallies seeking Verigan's Fist, for example?"
We don't know for sure. The alpha is not out yet, nor has there been any information released on this subject since BlizzCon. What we do know is that at BlizzCon they talked about these dungeons being heroic versions of the older dungeons, which would lead me to believe the previous versions of them would still be available for low level characters to run.
But that's just speculation, the only legitimate answer is that we don't know yet.
"Are there any sites that list best in slot gear for level 60's without the BC expansion?"
While it doesn't say "best in slot" exactly, Kaliban's Class Loot Lists still has the level 60 version accessible.
Gamer am I asked...
"Why can't we buy weapons with emblems, but we could but them with badges in Burning Crusade?"
Badges in BC got out of hand. The gear you could get with them, from armor to weapons, at points rivaled what you could get from the latest raid content. Blizzard has learned from this mistake and toned it down a notch to a more acceptable level. If you want weapons, you're going to have to run instances and get them as drops. Item level 232 weapons are available from the heroic versions of the Icecrown 5-mans, but you're going to have to farm them; not jut run heroic Violet Hold for a month.
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