Broadly agree with you but Canon and Nikon APS-C are not one stop better than NEX (can't comment on Samsung). Nikon may eke a little more out of the Sony sensors but overall there's nothing to choose between the most recent sensors implemented by Nikon, Sony or Canon.
I know that some of the sensors are the same across some of the brands. But then again, this leads me back to implementation. Looking at the RAW files that dpreview provides and in their widget, the Nikon D7000 lookst to be a 1/3 stop to 2/3 stop cleaner at ISO 6400 than the NEX5. Looking at DXO mark, they report about the same, a 2/3 stop difference in noise and about a .5EV in dynamic range. While this seems like "nit picking", if you take the worst APSC and compare it to mFT, we are only talking 2/3 to a stop of difference in noise and dynamic range. Even the Samsung sensor is only 1/3 stop better in some areas and worse in others than the GH2.
Moving to the 1/1.7 inch sensor reveals a different story however. Now we are talking 1 to 2 stops difference in noise, depending on the sensor(LX5, Canon S95..etc). While a 2/3 stop may not make a difference to some people(It doesn't for me, why I chose mFT instead of dSLR), a best case 3 stop or worst case 4 stop difference between a compact and an dSLR is pretty significant. Maybe this is what David is trying to say. On the other hand I have to respect these types of cameras that have decent and fast lenses and do provide convenience and portability at the sacrifice of Image Quality.
While professionals may be able to tell the difference, and this is very important in larger prints, other people just want to take pictures, which I know isn't necessarily the topic of discussion.
On a side note, I love to carry my PEN in my coat pocket. Nothing else goes in their though. During the summer the camera goes into the extra pocket of my cargo shorts. Again, nothing else goes in there. This allows me to carry my camera around without it being exposed and clunky. Just personal preference. When I hike or walk in the cities, I usually keep it on a sling.