I played Demons Souls but I never summoned anyone to fight with me, or did I ever get summoned or go to another person's world. But for the first time since I started Dark Souls, I went human again then went straight on to fight the bell tower gargoyles. I summoned 2 phantoms, and we killed both gargoyles in literally less than 2 minutes. Then I went back to the Darkroot forest and fought that butterfly thing, again with 2 summoned phantoms and it was SO easy.
At first I was skeptical of the humanity system and becoming human, but that alone makes it worth it. It adds so much to the game to be able to fight with others; I suggest you try it out if you haven't!