@tdicola
I agree linino is not a full fledged Linux and I agree that multiprocessor programming is not easy.
I however fully disagree that those are the problem end users are reporting here.
The problems I have seen or heard reported here are
- liability ( sketch using bridge run maximum for a week) .
- fileio library size() function is not developed yet
- the yun crashes if you read big files from the micro SD card using fileio library
- ttyACM0 is unstable
- WIFI are not usable.
- DHCP lease not work.
These are not things related to "not running a full fledged Linux" nor to "multi processor complexity". These are related to linino bugs and a badly written bridge (they use the string class using 2K mem of the 28K available 
)
I for instance have a yun like solution ( linksys wrt54G running openwrt and a arduino Mega connected via serial port) running for more than a year now with less problems than the yun.
So I think I know about the limitations of openwrt (my linksys has less memory and disk storage than the yun) and I know about multi processor programming (I have a bridge like capability in my solution) but I seem to be unable to get yun to work reliable.
The most striking example is that when I turn the yun on my sketch does not start (even if I call mcu-reset in the boot process of linino) but it does when I upload the very same sketch when the yun is running.
I personally believe that the yun is a very strong player for the embedded mobile market. But the arduino core team has not done their homework properly enough to build a reliable tool based on the yun. It only works fine for a small fun breadboard application.
I really hope the Arduino core team fixes these issues soon (like in yesterday)
Best regards
Jantje