The Witcher 3 was their first PlayStation release ever, so it might have some issues at launch (I don't recall any serious ones with PC and Xbox One versions, since they had more experience with those platforms already), but I imagine that by now they are far more comfortable with the hardware. Regarding things like animations, Deep Dive and the rest of the footage being shown behind closed doors is not really representative of the current state of the game, since it comes from 4-5 months old build. Things like animations, UI, character creator, etc. may already differ greatly from what was shown I believe.The thing that scares me of those quotes is that the game will be released in 6 months (with one of the main devs saying he'd prefer not to have a fixed release date???) and they are still adding things, with few months for optimization on 4 consoles and thousands of possible PC configurations, polishing and whatnot. Also animations are still a problem... And they haven't finished all the game's features yet? Oh boy, smells like delay incoming or another TW3-like launch...
Still the fact that the game is not feature complete and the things are still being added into it on one hand shows a great dedication to the final project, but on the other it also puts current release date in a serious jeopardy. If the delay happens, the game release will most likely be moved to the Autumn 2020.