Olly OM-D E-M10 Good idea?

There is nothing wrong with this camera in terms of image quality it will perform about as good as a Canon 7D. That's not a matter of Olympus being good, but Canon being so far behind with their APS-C sensors that its a joke.

Where you will suffer is from the slow AF speed, the Canon 5D is no speed demon itself, but the 7D is and you may miss this. I've taken plenty of good photos with my E-M5 though and wouldn't fault it. It's just not really cut out for fast moving birds and wildlife.

You could do it with the E-M1 but you'd have to want to spend the cash for that body and by your implied way of thinking I'm not sure you want to spend that kind of money. The 14 F/2.5 is a fine enough lens, and the 28mm frame is a pretty good one, not to long not to short, pretty much a modern "standard" lens, you wont have any problems should you decide to go down that pathway.

I like my E-M5 but I don't shoot action photography and if I'm shooting birds it's generally the type that will come to me. Food helps with that process of course, but its a demonstration of ways around that problem and it allowed me to get a speckled pigeon and a Tree Parrot in one shot. Those dragon fly shots are a whole lot of luck more than anything else.

The E-M10 will produce largely the same quality of images with two distinct advantages, those being, 0 second anti-shock and focus peaking, although you do give up the 5 point IBIS, weather sealing and grip extenders you can get for the E-M5 and E-M1. The grip for the E-M10 is just not very good. It doesn't add enough bulk to change the dynamics of the camera and the E-M10 was too fiddly in my hands. There is always the fotodiox grip if you want more grip, but it doesn't reposition the shutter button the way the battery grip does on the E-M5 so you're faced with the old Canon style reach around to get to your shutter button which is no good if you've got smaller hands https://www.fotodioxpro.com/fotodiox-pro-all-metal-black-camera-hand-grip-for-olympus-om-d-e-m10-mirrorless-digital-camera-with-battery-access.html