Sounds like poor technique to me no offense my friend but practice your foot placement (if anything) and makesure you run at the right angles and stride of force. I can almost guarentee its not your shoes becasue I have these pair of adidas bounce that I have beeen running in since they came out early this year. I run almost five times a week, sometimes in the rain and wall runs arent affected by the soles.

i doubt the shoes matter at all, just try placing your foot on the wall before doing anything, and find the right solid angle, and then apply the force.. and see if it slides or anything.. its all a matter of foot placement angle + force i guess

atleast thats what i do, i kick the spot a couple of times as if im performing the move, and adjust on how compact and stable it feels

There are three things to consider, and by order they go like this:

Technique
Surface
Shoe.

Most important is your technique, you must have proper momentum so that a push/slide is not even needed, but instead a kick/punch to re-direct your force to the desired direction. You must have proper foot placement in relation to your body and direction, and that's being vague.

Next is the surface of the wall. I have two of the best shoes out there, the 5.10 Freerunners and the Ariakes, and even they cannot stick to certain walls, such as painted, dusted, and other such slick walls. No shoe can. You'll just have to compensate with upper body pull on a wall up, or speed on a run, etc etc. Always test out the wall as mentioned before me, and see how it feels. The best walls are brick, cement, and most rock walls. The more rugged the better. Pick a wall you wouldn't wanna brush bare skin on. That wall will give the most friction.

Finally is shoes. Not a quarter as important as either of the above elements. I've seen people wall up with converse better than someone with ariakes just because of technique. The only reason to spend lots of money on shoes is for durability, comfort, and support. I'm not saying grip doesn't matter, I'm saying your shoes are the least likely culprit of bad wall techniques. It's the first excuse beginners shoot for, because it's the easiest to solve, it takes the blame off them, and who doesn't want some new shoes.

As a tip, make sure you rub off your shoes before a run. Walking on the ground, the shoes pick up lots of dust, and a fervent filing of your shoes will really help you out.

Hope that cleared it up for you.