I don't think that removing MCAS has been clearly ruled out yet. The AVCanada employee would most likely not have mentioned it in an eternal email if it was not theoretically possible.
I think a plausible scenario is that Boeing is contemplating going down the MCAS removal route and they are leaking the possibility of a line shutdown to put pressure on regulators (through the political process) to allow a RTS without MCAS.
lol. So together with mcas removal they will also be using downgraded engines, i.e. building the 737NG again, or what are you attempting to say?
Bjorn Fehrm speculated that aft lower fuselage strakes could be an option to aerodynamically provide the desired behavior. In level flight, the drag should be small, but there still would be a lifetime cost impact to an approach like that.
Just throwing out half-educated guesses here, but perhaps fitting a CFM56-7 sized fan on LEAP and reverting to the former engine location would cost 5% additional fuel consumption, while strakes might be 1-2%. If so, that would strongly favor a feature like a strake change over the engine modification. I suspect development and certification schedule would also favor the same path.
That said, I'm skeptical removing MCAS and resolving handling concerns another way is necessary. If anything this drastic was necessary, then either it should have been clearly communicated already by the FAA, EASA, or other agency, or it must be a new determination, such as from the simulator sessions. To be clear, I'm aware of the EASA questions, and I presume Boeing has been engaged in regular, detailed discussions with them ever since, so any new determination related to them contrary to Boeing's current plan in work would be a major surprise to me.
Since the reporting on the simulator sessions revolves around clarity of the cockpit information and the crew training and response, it still appears to me unlikely that any agency has indicate to Boeing an intention to withhold certification until the intention of MCAS can be fulfilled without MCAS.
At the same time, I'm not going to waste any mental effort imaging scenarios under which any agency would certify the MAX with the current aerodynamics, but without MCAS. The crashes have only heightened, not diminished the concern of risks like less-than-linear column force approaching stall.
BTW - you can still stall a MAX even with MCAS 1.0 or 2.0. It will not stop it from happening if you are determined. It is not Envelope protection.
Perhaps we need a new term. How about "envelope encouragement?"