The trouble with time travel

Rating: 6/10 (6 January 2013)

I love sci fi movies and futuristic ones, even if the future is a deteriorated version of the now instead of an improved one. The trouble with time travel is it always leads to plot holes and this one had a couple. The movie was good except for some nagging logical inconsistencies. So I am going to talk rather openly about the movie, though you may not fully understand unless you have seen it.
Joe BW - the Bruce Willis version of Joe 30 years older, Joe JGL - the younger Joseph Gordon Lovett version of Joe
Joe is a looper, killing people from the future. When your loop is closed, the last person you kill is yourself with a big pay out. Then you have 30 more years to live until you are the older version of you sent back in time and killed by yourself. So Joe BW kills himself when he is young and lives out the rest of his 30 years. Most of it still living a drugged violent life until he meets a woman who cleans him up and makes him anew. When they come to send him back in time, his wife is murdered. So, Joe BW who is now a very skilled killer manages to jump back in time and survive Joe JGL trying to kill him - this is already a change since Joe BW killed his older self. Joe BW comes up with the plan to eliminate the rainmaker, the terrible gang leader in the future he feels is responsible for his wife's death. I am guessing all along they were killing people for the rainmaker??? The idea is killing the rainmaker will save the wife and keep him from being sent back in time. Right? Another key point, though Joe BW exists at the same time as the younger Joe JGL, whatever happens to Joe JGL affects Joe BW. Joe JGL cuts himself and Joe BW gets the scar - time travel shouldn't work that way, Joe BW should solely be the product of the life he lived unaffected by changes he causes, but these are the rules the movie sets up which also contributes to the plot and the plot holes. Also let me add, the impression I got was the reason Joe BW survives his loop being closed is because of his wife, yet he obsessively checks his watch to make sure he still meets her. Joe BW when young killed his old self presumably because he didn't meet the wife and she didn't die. So since scars show up on BW's body, if the future is changed so Joe JGL doesn't meet the wife, Joe BW should disappear.
Anyway, Joe BW's plan is to find the rainmaker who is still a child and kill him to change the future. As Joe BW is about to shoot the rainmaker's mother to get to the child, Joe JGL has an epiphany about what made the rainmaker so bad and kills himself to stop his older version Joe BW. The idea is Joe BW killing his mother is what makes the rainmaker evil. Here is my issue, in the original time-line, Joe BW had nothing to do with the rainmaker and therefore had nothing to do with what turned the rainmaker bad so even without Joe, we still risk the rainmaker being evil. Second, if the rainmaker is who sent Joe BW back in the first place, him not turning bad would mean Joe BW should disappear as he was never sent back in time - also because Joe BW is not unique from Joe JGL, whatever epiphany Joe JGL has, Joe BW should have. So the fact that Joe BW only disappears when Joe JGL kills himself means that the rainmaker must still be bad and have sent Joe BW back in time. Remember, it is not Joe who is originally responsible for the rainmaker being bad. Every second Joe BW is there means that whatever has happened in the now has not changed the future.
The better ending would be Joe JGL having his epiphany about why the rainmaker turns bad changes the future. Joe BW who is about to shoot his mother should have the epiphany too and then disappear as the future is changed and he is never sent back in time. Then perhaps, Joe JGL can either go on his way or stay with the rainmaker and his mother to help protect them and ensure the rainmaker will be good instead of evil as he has potential for both.
Have you gone cross-eyed reading and trying to understand this? I still liked the movie but will still be waiting for a time travel story that can iron out the difficulties with time travel.