Another big strength for Austria is that all of it's victory conditions are extremely close and are easy to get very early.
The nations that neighbor you are also weak or easy to conquer, Prussia can be devastated by easily going for Berlin, Poland-Lithuania is large but has a small weak military, the Ottoman Empire is big but obsolete military and undefended Balkan regions, and you have many single region nations that can be easily wiped out in a single battle. Your starting regions and most of the regions that neighbor you are mostly catholic so religion unrest isn't too big of an issue. Map Position/Starting Stance Strengths: Austria starts out in the middle of Europe with multiple major cities ripe for recruiting they also have Hungary which despite not being a major city is still a good recruitment center.