I mean to say, at the point where the I2C library user has to seriously think about patching their kernel, the strengths of the RPi as an out-of-the-box embedde

I mean to say, at the point where the I2C library user has to seriously think about patching their kernel, the strengths of the RPi as an out-of-the-box embedded computer are pretty much negated. If you have to do actual embedded engineering things, then the RPi becomes just another SoC dev board.