How to deal with Astros...

[Amiaze]

Try running behind a wall and using <Blizzard 2> to bind them in place. Then that should stop them for awhile.

Thanks! I try to do that, but since it's something I've only recently adopted, I sometimes misjudged the range of the spell. It has been working for the most part, though.

Can someone explain what makes AST so good in PVP compared to SCH or WHM?

As the poster above me said, it's our ability to heal while moving. We also have two MP-restoration abilities rather than one and, if you count Stoneskin, have three different shielding spells that can all be used at once. With the right cards and a good team, AST is the perfect healer for PvP. Keep in mind that Essential Dignity is not only our strongest healing spell, but it's also an instant-cast. You can be in the middle of sprinting and it'll still work, and Aspected Benefic I only takes a millisecond to cast for a quick regen/shield.

That being said, those skills only do so much and can only be used so often. Once a focused DPS or WAR comes your way, a small shield or quick heal won't really suffice.