I will say it's difficult to have both an easy and intuitive GUI as well as a complex yet easily accessible feature set. Heresphere scares the shit out of everyone who first sees it, but it only takes a couple of hours to figure out. DEO does a great job at being easy and intuitive but there needs to be a hidden advanced mode to match Heresphere, with detailed menus for every easpect of camera and color correction as well as keyframing. You can't even adjust exposure without breaking the image in DEO so it's not just about features, there also needs to be work on how the image is adjusted.
And there's no compensation for scale adjustments like in HS, where distortion in scaling is well balanced through the autofocus feature. Essentially, if you adjust l/r eye distance to change the scale, in DEO you get a headache, while in HS AF helps to present the adjusted scale in a more natural way. Not sure how this is achieved but bottom line, scale / zoom adjustment in DEO is poorly implemented compared to HS.
You know what feature would leap ahead of HS? Auto color / exposure correction and auto camera correction. Basically fixing all the shit that should have been taken care of by the original studio. Just aim for that, and no need for complex user adjustments.
