It should be quite a common sight to be honest, Naxx brought that change exactly because it also added a ton of deathrattles. Imagine, for example, a Creeper and an Unstable Ghoul die together to aoe. If Creeper was played first the spiderlings die to Ghoul's explosion, otherwise they spawn after it. A ton of similar interactions happen all over the place, I guess it's just that Sylvanas was the first one you remembered. :P