What would really be cool is if they would allow you to choose from an assortment of vendors with different goods/services for the 3-person mounts, and if you wanted to switch them out for whatever reason you could go back and do that at the vendor.
You can see the Water Strider being ridden by the NPCs to the north east of Binan Village in the Kun-Lai Summit zone. They move very fast (the animated movement that is not the forward speed) although there is no way to know if this is the same as mount versions.
They also make a lot of noise which might be pretty distracting, though perhaps forgiveable for the utility of a water walking mount.
Buggy Arthas was fun. My server had Arthas and Orno Grimtotem in Orgirimmar. All the guards were ganging up on Orno, while being TOTALLY oblivious to Arthas that was standing just inside the Inn! Was a sight to behold.
I think the 14 slot bag isn't bigger because they don't want to steal too much thunder from the professions, especially tailors.
What's the point in having someone that can tailor big bags if you can buy them cheap from a vendor?
To all the people complaining they can't afford the Yak, it's not supposed to be fore everyone. It's not supposed to be something most people just buy, take a small hit and farm the cash quickly again.