I have mixed feeling about it, mostly because i think it will be abused. But if i had to choose, im pro choice just because ive been looking forward to something different.
I'm really hoping for the best, but they refer to it almost as "animal training." And they mention that you train summoning by having the creature follow you. To be honest, this sounds like a potentially dumb update. Ah well, we'll see. I've lost most of my faith in Jagex though.