Just a thought but what apertures are you using in your shots? Don't forget that M43 depth of field at f8 is equivalent to f16 on full frame. I hardly go above f5.6-6.3 (landscape work) on my M43 system and I'm happy with the results compared to my full frame camera. I see lots of people going around using f8-f11 on M43 for no good reason - you're just cutting out lots and lots of perfectly usable light which will result in significantly more noise.
If this doesn't apply then no worries
I certainly agree with you about the depth of field differences, meaning it is wise not to stray above 5.6 for sharp images. However, the idea that using a higher f number will automatically result in higher noise is incorrect. Assuming that you have decreased your shutter speed (longer exposure) accordingly, the number of photons recorded and hence the noise level will be the same.