Allow me to take you back to November 2004, when World of Warcraft was brand new, and Hunters were gods among men… also they were a dime a dozen (now it’s Death Knights).
Now come back to the present.
As you can see they made not only a huge change to the talent, but completely redesigned it. This change occurred in patch 1.7 (this was the huge Hunter overhaul patch), and used to be the final tier talent in the BM tree. While it wasn’t incredible, it was definitely worth that last talent point. It only required 1 talent point (instead of 2 now), and had three ranks. Ranks 2 and 3 were trainable at levels 50 and 60, respectively. It healed for 20/30/40. It took very little mana to cast (around 200), and did not have a cooldown. You could always keep this buff up, and never have to worry about your health. Combine this with a very fast attack speed pet, and you have a healing machine.
I was actually a little miffed at Blizzard for making such a huge change to the talent. This talent was fantastic for raiding since the healers wouldn’t have to focus on you as much. For leveling and grinding, it lessened down time (not that we ever had a problem with that). For pvp, I only really ventured in Alterac Valley in those days, but I hardly ever died because of this talent unless 2-3 enemy players were focusing on me. I could send my pet on someone to disrupt casting, and focus on another person, all the while getting healed.
There were numerous times while farming in Burning Steppes that I would aggro 2 mobs while farming Thorium. One would focus on my pet, and the other would come to me and start wailing on me. Spirit bond would keep me healed (often out-healing the mobs damage to me) until I was able to focus on the second mob. It was also incredibly helpful when I was trying to solo Volchan when he was around.
Spirit Bond was such a brilliant talent, and probably belonged in the survival tree (that got Lacerate instead, lol). Why they nerfed it as badly as they did, I’ll never really know, but damn I miss the old Spirit Bond.