I find the H to be an extremely stable platform in flight. Where imagery is concerned it provides one of the best stabilized gimbals available. Where flight stability is concerned I find it's quite stable. We should not confuse control function sensitivity with stability. I prefer an aircraft that performs more like a hare than a toad, which is an area some have issues with the H. because they are slow they expect the aircraft to respond similarly. One of my greatest disappointments with the H have been the firmware releases that have "de-tuned" the aircraft's control response from what it had been originally.
I had a fly away last year and Yuneec took care of the problem. No problems since with either of two H's. At a $1,200.00 price point I didn't expect perfection, and still don't. What I'm considering now at a $16,000.00+ price point does not achieve perfection either. In fact, the 520 incorporates much of what is available in the $16,000.00 rig, except for a higher end camera, ability to incorporate far more payloads, and flight controller flexibility in programming.
Those that have out of focus edges on their images can fix that by aligning the lens (centering it) a little better. Or complain to Yuneec and have them correct it. Or change out the original lens for a better one. I don't see where Yuneec has ditched anything, they simply introduced a commercial level rig for commercial level operators. The H is/was a bridge between hobby and low end (meaning "every and anybody" type) professional work. It still meets those needs quite well. It can fly a lot better than most of those flying it.