Anyone upgraded from GF-1 to OMD EM-5?

I found that the 45mm f1.8 missed focus on my E-P1 a lot, so I don't think the problems you've had are as a result of a Panasonic-Olympus compatibility issue. The greater number of AF points the E-M5 has compared to the E-P1 and faster, more accurate AF overall contribute, I'm sure. I'd guess you'd see an improvement with the newer Panasonic bodies with the 45 1.8, too.