This was a minor problem I noticed in WOTLK but since Cata was released I have experienced this problem with alarming frequency. Basically I have been rezzing with either no pet (even though it was alive when I died) or rezzing with a different pet than I had when dying (using felhunter and constantly rezzing with the imp). I either have to wait to rez a pet or burn a precious soul shard to get one. Since we don't rez with full soul shards however, sometimes I don't have one to burn, and if I did I then have to use soul harvest to get them back while my teammates are off being productive.
Anyone else noticed this recently?