The demand for batteries in all shapes and sizes for everything electronic just about guarantees constant research, development and improvement. I think that's a given.
The new holy grail for me would be new or improved technology to create FOOLPROOF tanks with long-lasting coils and wicking, as well as consistent vapor production, THAT DON'T LEAK..........E*V*E*R!!
I can't tell you how many times, as newer tanks become available, that I have been in vaping bliss, only to have to stop and fool around with or rebuild the coil. I don't mine rebuilding. Fun much of the time, but tanks (COILS in particular) have a nasty habit of breaking down at the most in-opportune times. Aspire, Kanger and others seem to be making great strides, and we may be almost there. I, for one, can't wait.