Thinsulate is fabulous!
If you're encountering wool coats which aren't warm enough, though, they probably aren't thick enough. Thick, lined wool coats are EXTREMELY warm. You can also get down "puffy coats" which look more dressy. What I find is that typically longer coats/jackets* will look more dressy and flattering than shorter ones if they're not a Columbia extreme outdoor weather jacket or something but they are meant to really keep you warm.
*Disclaimer: I do not know if there is a differentiation between coat and jacket when talking about winter outerwear, so give no significance to which word I use.