I have to agree with you. Actually, I find Basenjis entirely predictable. When they surprise you, it is often by doing something "good".
Seriously, if you want to consider being reliable off leash, some breeds are known to be far easier to train in this respect than others. If I see a badly behaved off leash Border Collie, Sheltie, Aussie, GSD, Golden, Lab, etc. I assume immediately that the dog has been poorly trained. With a hound or terrier breed, I accept that although the owner may actually have worked very hard on training, it is more difficult to accomplish a good result, and I would not be so quick to judge. The difference, to my mind, is motivation. Some breeds have no higher priority than pleasing their owner, which makes it a snap to have a reliable response if you have any clue at all about training a dog. Other breeds don't really care all that much if you approve of their actions, and will do whatever most pleases them, not what most pleases you. So the trick is to find something that pleases both of you…...not always an easy task! And if the only reason the dog responds at all is to receive a treat, you are done the minute something that trumps that treat appears. You need to condition a response, not always the easiest thing to accomplish with Basenjis and other like minded canines. JMHO.