Can they be better? Sure can, I think. But there is a 'but' to getting too much better, and that's a psychological 'but' (and this goes for part of us, not all)... that's the 'tinkering around with them' part.
As we come from analogues, we need to shed a number of habits, a number of actions, a way of behaving. And that's HARD. When going to e-cigs, we wade into this deep valley filled with unknowns, with failings and ways to fix those, with tons of things we have to learn to do or not do. We are busy, as the 'pioneers', to find adjustments and better ways of doing things.
I'm convinced that all of these things that we 'wade' into when going e-cig, are very beneficial for us as to being able to shed all we need to shed when leaving behind tobacco. And when the days arrive that we will be getting one simple device with one tamperproof nicotine-holder inside it, with no need but also no possibility to mess around with making our own flavors, finding new ways of doing things, finding ways to repair what's going wrong or ways to stop repairs from coming... when those days arrive, I predict that the e-cig will become far less succesfull in converting people from analogs to vaping, compared to now (again: this is for part of the people; there is also a, I think smaller, part that will just sigh with relief and sit back all content with their generic all-the-same-unit with unreachable but also not needed to be touched parts and nicotine-holder).
Just my thoughts on it; but I don't think this aspect should be forgotten or discarded all too easily.
