One has to wonder if "Jacob" was really the bad guy. Everyones life he "touched" seemed to go to hell in the real world:
Hurley - from nothing goes wrong, to everything goes wrong
Locke - May be in a tough place paralyzed but now seems to be getting his life together with his fiancée and new job
Sawyer - after meeting with Jacob his mom fell into the con man
Jack - Life in real world fell apart after Jacob encounter
The list seems endless. We seem to see a much better life for all the Jacob victims if he did not interfere.