For my money, I'd go with High Efficiency Masonry Heater. It takes full advantage of the already accepted term (masonry heater), and clearly denotes itself as an improvement.
No arguments from insurance companies or building codes.
Anyone interested in a Masonry Heater is (more) interested in an H.E. Masonry Heater.
And I don't think you necessarily lose the familiar Rocket Mass Heater name either. It is super common for a thing to have an official name and another name used by people more familiar with it. Salesmen would likely never use RMH, but they would also only talk about H.E. Heaters when selling.
But I am in the camp that thinks it's not just the name holding back large scale adoption. RMH tech needs to be taught to architects, builders, designers, and contractors. Normies don't consider if they could heat their homes using their fireplace. That thing is just a luxury that came with the house. To take over the world, these things need to be built in new construction and/or included in a designers work on a remodel.
I'm getting long winded now, but I also think it'll take some plug and go plans for full builds (not just shippable cores, though include those). And (don't hate me for it) some solid, good looking examples that aren't cob. (Or are covered cob). Using materials and techniques builders are familiar with would go a long way.
It's stupid, sure. But average-dude doesn't care that it costed him $2500 to build what you did for $300, he just wants to source it from Home Depot and go on with his life.
