They have complementary advantages...first the 5DMKII has PDAF which has certain advantages with very fast focusing lenses for sure, but its also a non-pro level PDAF system and therefore very bare bones. My E-PM2 touch shutter AF is absolutely amazing...no more getting terribly out of focus shots when I hand over my 5dMKII to a family member (happens almost all the time). If they can use an iPhone they can do spot on shallow DOF focusing on an E-PM2.
Yes I'd expect the Oly to do well if you are comparing f5.6 to f11 on the 24-105L. First of all however you can buy a cheap 50mm 1.8 and still get ridiculously good performance on a 5DMKII at f4-f5.6. I'm no landscape photog, but this is my stopped down $80 nifty fifty on a 5dMKII. In any case you are comparing apertures for which many lenses on the 5DMKII are already quite good at f2.8 and peak at f4. On the other hand MFT is no slouch, many lenses very strong wide-open...some even near peak wide-open. Almost no FX/EF prime lens will be anywhere close to peak performance especially on either FF or APS-C sensors.

I don't like the 24-105L for size/weight reasons alone as well as IMO actually being quite inferior to many non-L primes. I'd rather have the 40mm f2.8, 50mm 1.8, or 85mm 1.8, etc...
It is with these cheap non-L primes that even at f2.8 for many of them, MFT may start to struggle...a bit to replicate (basically they can't compete in DOF here and many primes are plenty sharp with low CA here). At f3.6-f4 many of these primes really start to peak in resolution, and exhibit no CA, etc.
However for travel, and family events, sometimes too much shallow DOF ruins the shot anyhow...
Finally EVF's do not replace OVFs for me at all so I take advantage of exploring different shooting/framing methodologies with either system. Touchscreen LCD with lightning fast and accurate focus anywhere capability is powerfully complementary to the rudimentary but fast and simple center point back button focus and recompose on the 5DMKII.
Happy with both systems...looking to pick up the 45mm 1.8 to see how it compares to my 85mm 1.8.
Yes I'd expect the Oly to do well if you are comparing f5.6 to f11 on the 24-105L. First of all however you can buy a cheap 50mm 1.8 and still get ridiculously good performance on a 5DMKII at f4-f5.6. I'm no landscape photog, but this is my stopped down $80 nifty fifty on a 5dMKII. In any case you are comparing apertures for which many lenses on the 5DMKII are already quite good at f2.8 and peak at f4. On the other hand MFT is no slouch, many lenses very strong wide-open...some even near peak wide-open. Almost no FX/EF prime lens will be anywhere close to peak performance especially on either FF or APS-C sensors.

I don't like the 24-105L for size/weight reasons alone as well as IMO actually being quite inferior to many non-L primes. I'd rather have the 40mm f2.8, 50mm 1.8, or 85mm 1.8, etc...
It is with these cheap non-L primes that even at f2.8 for many of them, MFT may start to struggle...a bit to replicate (basically they can't compete in DOF here and many primes are plenty sharp with low CA here). At f3.6-f4 many of these primes really start to peak in resolution, and exhibit no CA, etc.
However for travel, and family events, sometimes too much shallow DOF ruins the shot anyhow...
Finally EVF's do not replace OVFs for me at all so I take advantage of exploring different shooting/framing methodologies with either system. Touchscreen LCD with lightning fast and accurate focus anywhere capability is powerfully complementary to the rudimentary but fast and simple center point back button focus and recompose on the 5DMKII.
Happy with both systems...looking to pick up the 45mm 1.8 to see how it compares to my 85mm 1.8.