Great points, I agree - Povetkin is a very skilled operator with his punch technique and selection, I learned a lot from him. Parker could too, as you say!
I recently watched Povetkin go to work on Rudenko and Duhaupas and it's night and day to Parker's crude stuff. Povetkin isn't a substantially harder puncher than Parker, not at all -- in fact Parker might actually punch a little harder than Povetkin due to his greater speed and explosiveness -- but there's so much more going on with Povetkin that improves his effectiveness. He's brilliant at hiding his shots for instance, so fighters have a much shorter window of time in which to react to his attacks, and often can't brace for them at all, which generally results in knockdowns or knockouts. His left is tremendously versatile, not simply as an attacking tool but as a way to open up fighters to attacks from his rear hand as well. Watch him pepper fighters with quick tightly thrown hooks and uppercuts then suddenly dip down and throw an overhand right when they're least expecting it. Or crack them to the ribs when they're already hurting upstairs. Or catch them with a second (or third) hook off the same hand as they're moving back to defend a right cross. When he's not attacking he's constantly manoeuvring for position, dipping, stepping in, stepping out, moving from side to side, probing with his jab or feinting to throw power shots to see how his opponent reacts. When he throws, therefore, it's generally totally untelegraphed and hard to anticipate. His individual shots might not have the raw power of some HWs, but the accumulative effect of so many sharp, well-timed punches coming in from all angles to body and head is mentally and physically debilitating, and when a fighter doesn't know where an attack is coming from next even an average punch can do significant damage. That's why I think criticising Parker's power is misplaced. It's not his power that's the problem but his attacking style and delivery mechanism. He's too content to just blast away at his opponent's gloves and try to wear them down by attrition, and he lacks the heavy handedness to make that work. He needs to be picking his shots and working on opening up his opponents' guards more. Even a few of Povetkin's tricks would work wonders for his KO percentage, IMO.