OK - first, the doptre correction setting on the EVFs needs absolute precision. If you can't see pixels on the finder array, you either don't have good enough eyesight, or you have the dioptre set not quite perfectly enough. You should be able to see pixels clearly on your laptop or computer screen from normal working distance, even if you are using a Mac Retina iPad. The pixels on the EVF are relatively coarse compared with this. That's one issue.
Secondly, whatever JPEG setting you use, your EVF will display according to that. If you turn sharpness up, you'll get a sharpened EVF view. That also affects how well (or how discriminatingly) focus peaking works.
Thirdly, the A77 and NEX-7 both have a load of coloured noise in low light, through the EVF. The sensors use auto gain if you want it in manual mode (studio) but normally reflect how the shot looks. If the ISO goes over 1600 on Auto ISO, you get bad noise in low light on the EVF. But when it really gets bad is when you use flash. This turns on auto gain (like the setting for manual studio work) and over-rides the finder showing the actual image exposure effect. It also over-ride ISO limits, so the cameras will range up to an effective 12800 ISO for viewfinder purposes. With flash, the shutter speed is set to 1/60th or 1/160th but always to 1/60th in low light. That may not be enough if your lens is at f/11 for flash, to even show an image. So the camera turns up the EVF gain enormously.
Result - terrible viewing conditions for anyone shooting flash, in low light, at smaller apertures.
The A99 with its much larger sensor pixels and better high ISO noise, and even the A55 with its low contrast EVF and 16 megapixel sensor, both provide far superior dark/low light viewing with flash and significantly better with slow shutter speeds and normal picture effect.