Professions skills are split between expansions now, you'll have a separate skill bar for each expansion. There are still 950 profession levels in total, just that there is no one single progress bar with 1 to 950 for it anymore. Instead, there are 8 separate progress bars. (The only exception is Archaeology, because it will still have a 1-950 progress bar)
People are never going to learn that sites like Zygor Guides, Dugi, and other premium site actively search out accounts that leak and share the guides and close them down thus cutting off OUR SOURCE OF CURRENT UPDATES! They use methods much like Whoknowsit did by embedding an encrypted tag somewhere with your username or account number so they can trace the leak back to the account. Just as Whoknowsit did.
To make it easier to level professions to 800, most recipes will stay orange for 20 more points. This is a huge change! For example, the blacksmithing 780-800 part needed around 120 Demonsteel Bar and 60 Blood of Sargeras at minimum to craft 30 Waistguard. (you probably needed to craft 50 if you were unlucky). But now you will only need 20 Demonsteel Bar and 10 Blood of Sargeras to craft 5 of them.
No. Never. Buying leveling guides is a waste of money. Any type of information covered in Zygor is more or less found all over the internet. Leveling is so fast and streamlined now there shouldn't be a reason to use a guide. Go to the zone recommended for your level and do about 20 quests and you're already on to the next zone, outlands, northrend, and cataclysm content is so fast now you can do all 5 or 10 levels of the expansion in one or two zones.
The best part about the guides, though, is that you won't be sidetracked by various other quests. For example, if you're a dwarf questing through Eastern Kingdoms & get that random quest that takes you to Feralas, Zygor will keep you on track by putting that Feralas quest on the back burner while you keep chugging through the main storyline in Eastern Kingdoms.
Anyway I will go ahead & download the Twitch app like everyone's saying, but I still need to know whether my in-game addon settings will carry over automatically, or whether they'd return to default same as if they'd all been uninstalled in the curse client then reinstalled from scratch. Because if it's the latter then I will have to take screenshots of the settings on all my toons BEFORE I install the addons thru the Twitch client.