Late to the Conversation.
Showcasing what to expect in the game for a boarder audience is the smarter move. So long as the ultimate vision is the same, I don't care how they package it only that it gets shipped.
If I understand it right, the Vision is the same, it's just that to the majority of players they will be more interested in the Action, Wifu, Kiju, and Mecha. Thumping is still a core part of Em8ers game design as well as the Open World PVE, however most people just want to fight giant monsters in mechs. I think this is perfectly fine for a kickstarter demo.
Rather than showcase the Overworld stuff that the majority of the current loyal fanbase is all jazzed about, its easier and safer to market the Fighting to the masses. Firefall had good feeling combat, Em8er seems to be going the same route as far as the Demo is concerned. Its a smart move to show off what most people want, to sell the game to people, and use that capitol to build the rest of the game.
Mark has not changed his mind on the vision, only the execution of said vision. If he came out and said Thumping as a mechanic was going to be wholesale removed, I'd expect many would be rather upset about it. This is not the case.
Edit: On giving it some though I think it would be best to market the Demo as a 'Combat Showcase' to ease some minds on what is going to happen, and that the game is not taking a drastic 180, still a smart move to do, but clarification will be key in any communication. Mark loves to go with his ideas, they are good, however he has a problem communicating them clearly. Love him to bits, he is just on the spectrum like most of us.