For me, the biggest disadvantage is 1. the fact one is encouraged to leave the bees alone encourages swarming
The most given advice is not to leave tbh's "alone" but that they benefit from increased observation. Not that one has to go through every comb every time, but one needs to keep an eye that the colony has plenty of room to expand.
yes I know all about some of the theories about small cell size etc but, and it is a big but, there is very little scientific evidence to date, more theory and conjecture to back up ideas.
'small cell' is a concept associated with frame foundation. in a TBH, the comb and cell size is determined by the bees as it is drawn and one comb will have various cell sizes. Bees have survived approx 150 million years in 'natural' size cells and comb, I think that should stand as evidence enough for it's efficacy.
In terms of mites, they have been found to have lived with honey bees in various parts of the world for a very long time and there are honey bees in those parts of the world who have been found to have become tolerant and more hygienic as a result. Hence the introduction to the U.S. of the 'Russian' Honeybee as a response to the mite incursion.
This 'hive envy' that is displayed by one side or the other is a bit pesky and really only serves to show ignorance in action. There really is no need to criticize any one hive as bees have been known to independently move into anything from a tree to a house wall to an old car or camper.
Think of it in terms of a tool that is designed for a specific purpose.
Langs were designed to force increased production of honey and to make culling said honey easier for the beekeeper. Plain and simple and they succeed very well at what they were designed for.
One could say the tbh is designed for a more 'conservation' oriented approach to working with bees and is a tool that offers what those people using it consider a less overall intrusive and more 'bee friendly' environment at the expense of convenience or high honey production.
Use the tool that suits your objectives best and let it end at that.
I use mostly tbh's in my endeavors for the present and future but I have langs I use for purposes they meet best as well.
enjoy the bees