I believe Voidhawk was speaking to outcomes versus the usual list of advantages cited for ME versus SE. Worth reviewing both the last 27 NALL reports and other analyses of non-airline aviation accidents to understand the data on SE vs. ME accident and injury/fatality rates related to mechanical failure. Summary: pilots injure or kill themselves in engine loss/shutdown situations at a significantly greater rate (2x to 4x, depending on how the data are parsed) when an engine fails/is shut down on a ME versus SE. Lots and lots of reasons for this, including mission profiles, higher speeds at landing/impact (w/related V^2 effect on energy to be dissipated), variables in training and proficiency, the conditions into which a ME airplane driver is comfortable launching versus SE, and the usual ADM issues which a second engine adds when the first one fails, etc. This is not aerodynamics, but instead acknowledgement of the same realities which generate all those notes, cautions, and warnings in POH/AFMs, -10's, -1's, and NATOPs, as well as yearly injury and fatality numbers in the NALL and regulator reports (FAA, TC, CAA, etc.). On yaw authority...every aircraft will depart controlled flight given the right set of flight/aircraft conditions and driver input, but at least for this discussion, what we should be concerned with is at what airspeed in level flight, zero power generated by critical engine & max on the other, and landing configuration we must operate to avoid that loss of control. I suspect it's not too difficult a task to calculate a ballpark number for Vmc, and then to verify that number during flight test...pretty sure it's been done before at least a few times. Yes - it may very well be higher than the minimum level flight airspeed either in a glide or with both engines operating, but it's unlikely to be anywhere near cruise. And yes, the airplane might 'spin like a top' if things get too slow, but competent ME pilots tend to try to maintain enough airspeed to avoid that particular corner of the flight envelope. Interesting discussion/project which illustrates just how diverse our expectations can be re: building our own dream aircraft. Might be interesting to discuss what mods might be desirable to avoid making Vmc higher than it absolutely needs to be.