Bye the way I was talking about litecoin, not bitcoin difficulty. I never mined bitcoin.
The LTC difficulty has been rising not as fast as BTC, but I guess it will be a completely different case when the new generation of powerful scrypt ASICs are delivered.
![Smiley](https://bitcointalk.org/Smileys/default/smiley.gif)
Litecoin isn't as stable as BTC is, it can crash anytime soon. Also, if they would be mining scrypt coins, they would use a multipool instead of just LTC to maximize profits. BTC however, is a different case, there isn't much stable SHA256 alt coins and their difficulty would rise very fast.