I'm really biting my thumb on this, because these type of 'area of effect' cards can be game-breaking (see Rain of Fire and Plague) when it comes to creature control. It counteracts poison wonderfully (non-upgraded) or it's a showstopper if you pull it off with Darkness (Eclipse + Autumn Wind (upgraded) is... well, pretty hard to fight against). There are good and bad benefits with this, but for some reason, I can't give my thumbs up on this one.
I think the element may be throwing me off (how does the chilling autumn wind 'heal' you?). Or maybe just the name in general. The cost of the card sounds decent though, so I won't throw it out my head yet. Do these cards work on immortalized/burrowed creatures, or no?