My only caveat with the wax method would be it might come out, easily, when cleaning in hot water. I have pulled the air tube off the head, be careful of the wick that just lays on top of the coil, and they clean up like brand new. Way better than a clearo can be cleaned and also easy to switch flavors as a result. The other "big" tip is to invert the silicon seal on the air tube if you use thick, heavy liquids. This will increase the flow of liquid to the wicks/coil and eliminate or reduce dry hits.
Now the big trick will be having them maintained during manufacturing exactly the way they are, without any so-called improvements as has happened with clearos and CE3s.
One worthwhile change, if it can be done without introducing leaks, would be a replaceable mouth piece as many have noted. Something a little smaller or even a flat "pipe style" tip would be nice as well but I'm afraid that introducing a second set of seals would open a big can of liquidy worms.