There has to be a reason for it all. Being able to pierce multiple opponents seems like a long shot but considering archers on Nirn can probably be more precise and stronger than archers on Tellus they may be able to pierce many enemies with specific arrows, but not kill them all.
Pushing enemies back seems pretty weird, an arrow that maybe has a stone on the end instead of a point ?
Arrows should never make you sneak better, makes no sense at all without magical enchantments.
How fast you can fire your arrows should depend on the user but not the arrows (unless they are enchanted), Also I think archery will be more about accuracy and the power behind the shot rather than firing rate in Skyrim, even though in Oblivion we sure could have used arrows firing like the bullets of a gatling gun.
Again the disarm should be about accuracy, I mean a shot through the palm with a normal arrow should be plenty to disarm someone.
Specific creature arrows could be interesting, but it may be hard to figure out reasons why certain types of arrows should hurt certain creatures more, at least beyond "flaming arrows" for trolls and "silver arrows" for were beasts.
I don′t want to shoot your ideas down but it′s something you′d need to think really hard on to figure out a good reason for a certain design for an arrow to do certain stuff.