I have recently masterd kiteloops and they are actually one of the easiest moves in kiteboarding.
The trick to learning to kite loop is to cheat.
First piece of advice is to forget about doing a back roll during the loop. It's almost certain you will get slammed in on your back. It hurts. Just do jumps with kite loops. It's easier and you can get to enjoy the view and the feeling of looping.
Start off by practicing looping the kite as you ride along. Ride and put the kite high then ride past the kite so it is a little behind you. From this position the kite is super depowered and you almost have to loop it to bring it forward again. The kite loops more beside you than in front of you.
The next step is loop transitions. Do a small vertical jump, position the board to ride in the opposite direction then downturn the kite through the window to send yourself in the opposite direction. You can start by cheating by waiting until the board hits the water before sending the kite through the downturn.
Once you get the hang of jumping and looping and doing it all together, you can start on working on straight kite loops.
Do a fairly small vertical jump. Allow yourself to dangle and swing a little under the kite so that the kite is a bit behind you (like your earlier practice). Loop the kite to bring it forward through the power. Again you can finish the loop with the board on the water.
When you get comfortable with these little dangley loops, start going higher and earlier. You will find it is easier to do a huge jump with a loop than doing ordinary jumps. It won't be long until you can do a full power redirection in the air with a big powered loop. It's surreal to be high in the air with the kite out beside you then for the kite to catch you before you fall.