Are the flying passenger mounts? Ground mounts are lovely and all, but once everyone takes to the skies will they become useless to everyone with cold weather flying?
I haven't seen any flying passenger mounts yet. Whether the passenger ground mounts are 'useless' or not with Cold Weather Flying is really up to the individual. You can still use it in the old world, you can still use the Mammoth's vendors. There are also places like Lake Wintergrasp where flying is turned off permanently so you don't 'cheat' and skip over all of the fighting to get from Point A to Point B. You and a bunch of your friends charging people down in a huge Mammoth is sweet.
If you don't care about any of that stuff though, yeah it could be seen as useless. It's an optional purchase, though. You don't need to spend the money if you don't want to do so.
if the "vehicle itself takes falling damage," what does that mean exactly? Will it eventually break and be unusable? Can it be vendor repaired like armor and weapons?
It just 'dies' and despawns, kicking you all out. And then you resummon it and hop back on. No repairing, no vendoring, no band-aids. It just dies and you summon a new one. No big mess. It just has its own HP bar independent of yours. I guess you could see resummoning it as resurrecting it, if it doesn't make any sense otherwise. Though maybe that makes it more confusing, heh!
How do gear and weapon enchants stack up? Mainly, are there leatherworking, blacksmith, and enchanter...erm...chants, that stack on one item?
No. You can only have one permanent 'enchantment' per item. So your Leatherworking fur lining will not stack with an Enchanting enchantment. You choose one or the other. If a Tailor embroiders their cloak, they can't have an Enchanter's enchantment there in addition to that. One or the other.
Sweet Sweet SoulShards asked...
Can you tell us more about the new Slash Commands and Emotes in Wrath? Is /cower the only new emote with an animation?
There are actually a lot of new emotes, too many to just make a checklist here. However, WotlkWiki.info has them all listed. As far as animations, only /cower has a new animation as far as I can see. Some of them, like /mercy, share animations with older emotes. /mercy and /beg have identical animations, for example.
With 25 man and 10 man raiding, the gear is "one tier" above in 25 man. So, for example, 25 man naxx gear is equal to 10 man whatever comes after naxx gear?
So wait,...we get a pet UI and a mount UI, but no tabard UI, and yet there is a achievement for getting 25 tabards (which I am strangely drawn to do)? Am I confused, will there be a UI for tabards, or are they just going to clog my bank?
They're going to clog your bank until you earn the achievement. If you want to, you can get rid of some of them afterwards because there is a vendor in Dalaran that will resell most tabards to you for cheap, when you want to toss on an old one. I wouldn't go throwing away things like the TCG Tabards or the limited edition Argent Dawn tabards and the like, you won't be able to get those back. If you want to throw out your Outland tabards, though, I think it's safe. You can get them again pretty easily