I think it's usually a mistake for Italy to go after A-H right away, but I mostly say that for self-preservation because I always draw A-H.

If you're Russia, though, Russia/Austria is better than Russia/Turkey, IMO.

As Italy I tend to favour an alliance with Russia to an alliance with Austria, or Turkey, although it depends on the situation.

As Russia I tend to get crushed up north and spend my time trying not to do the same down south before Germany comes along and finishes me anyway. When that doesn't happen...I prefer Turkey as an ally because he can control the med and tie up the Anglo-Franco alliance that usually forms against a juggernaut, whereas if you go with Austria he's stuck between Italy and Turkey, and if you go with Italy he usually ends up getting more out of it (total med control and a solid base in the Balkans/Austria)

As Turkey, I don't mind an alliance with Austria because its ridiculously easy to stab them later usually. I'm not particularly choosy on my allies as Turkey, as it's just as easy to go with any of the other 3 depending on the situation.

As Germany, attacking Austria while both England and France are alive is idiotic and so you should never attack them off the bat.
If England is dead it can pay off if France has lots of fleets to flood the med with and he's not all over your borders. If France is dead it can work if England is both in the med and attacking Russia.

Austria is in a class of its own for vulnerability. Its 60% elimination rate is 20% higher than the next tier of countries (Germany/Italy/Russia, the other 'vulnerable' countries, sit around 50% eliminations) and more than twice that of Turkey, the 'safest' at 27%.

So no, it's quite common.

Germany is a bad candidate for attacking Austria simply because Germany's already in the middle... why expand further into the middle? Italy can work quite well, but generally requires a solid commitment from Russia to continue the alliance through the elimination of Turkey and Turkish cooperation or noninterference with the Austrian carveup. Russia can definitely profit from an Austrian invasion, but again, unless it has Turkey and Italy at each other's throats afterward and solid commitments from at least one (preferably both) to attack the other once Austria dies, Russia is inviting disaster. I think Turkey actually has the best case for keeping Austria alive, simply because it's just too easy for Russia and Italy to ally and squeeze Turkey out next. About the only way Turkey can really get away with it is if one of the Western powers can spare the forces necessary to attack across the major stalemate line into Russia or Italy before Russia and Italy get started on Turkey; and even then it's not really good, because now you're replacing proximate threats to survival with a distant threat to win -- better than getting carved up, but when there's a perfectly viable alternative to the whole situation in allying with Austria, carving up Russia and Italy, expanding across the stalemate line in the Atlantic Ocean and then smashing Austria late to win, why carve up Austria and screw yourself later?

The ultimate thing to remember with an attack on Austria is that SOMEONE of Russia/Italy/Turkey will come out a comparative loser. This doesn't mean don't do it, of course, just make sure you conduct diplomacy properly so that you're not the odd man out when it happens.

(I would also note -- perhaps to my later regret -- that refraining from attacking an experienced Austria early is not wise. Austria's only real weakness is its initial vulnerability; it's honestly one of the strongest powers in the game if it lives beyond 1903, because Austria is an extreme country. It never just languishes at a few centers throughout the game, like Italy; if it doesn't get outright annihilated by 1903, it's usually coming out of 1903 with 7-8 centers as a frontrunner. Ultimately you should play by personalities, neither resolving to attack nor not to attack simply based on the experience of the player playing the country and instead going after uncommunicative, hostile or otherwise unreliable powers. But an experienced Austria is a dangerous dangerous threat if allowed to live, far more so than most other powers.)