My type of photography: Never video Seldom fast moving objects, like kids, pets, sport. I think I shoot like a random tourist: a door, a building, a poster, a street, a landscape, a sunset, a tree, a car, etc. 95% of shots are outside. On the other hand I tend to behave like a hobbyist: I like to experiment with light: blue hour, etc. For bracketing or low light situations I use a tripod, which I like because of the slow process of thinking ahead, planning and executing. Roughly half of my shots are with legacy lenses, the other half 12-40, while I quite often use the MF option. My estimate is that around 60% is shot wider than FL 50. (I wish I could fill in the lens and FL in the metadata somehow) I have never used a flash. I always shoot RAW and I always compose using the EVF. Most of the time I shoot in A mode, while I fiddle with EV compensation. I am tempted to do that because of the wheather sealing (combo with my 12-40) and the 5 ax stabilization, because of my legacy lenses. Some doubts however: 1. I think I will going to be missing the fully articulated screen, but this will be no deal breaker. 2. When I rotate the focus ring of a native lens, the G5 automatically magnifies the image. The same applies for the EM5. When shooting a legacy lens, the G5 gives me the option to touch a focuspoint on the screen to get a magnified picture or pushing the rearbutton for the same effect. This is my major concern, because I dont know how the EM5 performs in this field.
That is a tough call, I like my G5 but I would probably make the trade. The main reasons I keep the G5 are things you mentioned: video, and the touch-screen focus point set, zoom pinpoint focus. You don't use video and Olympus is a somewhat nicer camera - stabilization, sealed, etc. You will have to acclimate yourself to the Oly buttons and menus which can take some time.
E-M5 would add stabilization and weather sealing to the 12-40, making it a much more versatile lens. E-M5 has a significantly better sensor than the G5. It's a pretty good upgrade, I'd say.
I've never used either camera, but I would think the resale value of the E-M5 is higher. Just did a quick check and G5's have sold for around $150 while the E-M5 sold anywhere from $260-350. I think the Olympus IBIS is pretty darn good. If you get any primes in the future, it will definitely come in handy.
I'd say since you get 5-axis IBIS, and own the 12-40mm lens which is not stabilized, go for it. IBIS is nice to have!
https://books.google.co.uk/books?id=dIuFAwAAQBAJ&pg=PT70&lpg=PT70&dq=olympus+e-m5+touch+screen&source=bl&ots=sAqdGxGbnC&sig=eWQgV8MJ_nqywakL9qQ3AzY5XmU&hl=en&sa=X&ved=0CFEQ6AEwCTgUahUKEwjjvou4iYHHAhUMchQKHdM-CyI#v=onepage&q=olympus e-m5 touch screen&f=false Link to preview of David Busch' book on the em5: shows the touch screen options, one of the functions is zooming on a focus area and you can adjust the zoom ratio between 5 to 14x. The magnify function is also available on FN1 button: press to activate and use 4 way controller to pick point then press FN1 again to zoom in. The zoom ratio is adjusted with either front or back knob. Edit: Hmmm, may be FN2 button.........
Having had a G5 and now an EM-10, i would do that trade in a heartbeat unless I needed e shutter or 1080p 60 fps video