Personally I dropped a point out of arcane stability to pick it up, but that was just because I find it useful. Of course you can probably get more dps by putting the single talent point somewhere else. If you need to slow adds down, personally I'd say to go with frost bolt or frostfire bolt. Not only does it do damage, but it can be applied to more than one mob at a time if needed. Slow is great, but I say that more for 5 mans/solo. There are plenty of times where a group gets pulled by accident, or you pull aggro with aoe etc. I've had plenty of times where I was glad to have it so I could kite a mob while finishing it off, or to save another group members life. I've never used it inside of a raid though as far as I can remember. Really though, it's only 1 talent point and if it helps your guild progress what's the big deal?