There's always a tradeoff...
Convection is the best tasting, most efficient method of getting vapor, but heating a heat exchanger to heat air requires a pretty large amount of energy. Doing so quickly is even more energy intensive, so you have options...
The MFLB has a rechargeable battery, but batteries only last a session or two. Also metal and wood in the airpath can lead to odd tastes, but they are durable and heat up quickly. Part of the reason the MFLB works at all is that it's heating up the plant matter directly rather than the air (at least in part). Heating air alone would take massive amounts more energy.
The vapor genie and other vapes like that are great in theory, but in practice, commercial butane is not pure, and even torch lighters produce NOx or CO if they're not reacting perfectly adiabatically. Long term inhalation of the byproducts of combustion of commercial butane remains unstudied.
My vapes are as portable as your torch lighter, and your experience with them largely relies on getting a decent torch. You can go through a lot of butane if you end up vaping all the time, glass is going to be more breakage prone than wood and metal, and if you're not careful it's possible to burn yourself on the hot glass. I still love 'em, though, because the flavor is unreal, and using a torch is completely manageable if you get a decent one. A case of butane will last years and years, as well.
It's really all about tradeoffs, simply because of the nature of the beast. We're lucky to enjoy ample power in our homes, but when you try to make something that uses a large amount of power portable, well, just take a look at the laptop computer. Li-Ion tech is great, but expensive, and lithium is a finite resource... once hydrogen fuel cell tech is really advanced, we may see smaller, better vapes, but at the moment you can only pack so much into a small package.