Before I became a Yuzu fan, I was a dedicated Dai fan (still am actually) and am familiar with his autobiographies and many of his interviews. Imo your characterisation of him is the most insightful one here and comes pretty close to my impression of him. The only thing I'm on the fence about is to call him fearful. I know he used words in that vein, but I think the English connotation is stronger or at least a little different from what he possibly meant to say in Japanese. He's not exactly overly self-confident. (And bar that first 3-year period under Morozov's tutelage almost always had been that way. That's why it wasn't specifically Yuzu's presence, which made him aware of his shortcomings. He often made himself much smaller than he actually was and even thought he wasn't really talented at all. ) He was fairly competitive when he saw a realistic chance to win, but had a tendency to get discouraged and dejected when he felt significantly inferior to his opponents or when any obstacle just seemed too high to overcome. Instead of going on the offensive and fight, he would give up or "run away" to use his own words. I think I'd call him rather insecure and tentative/evasive than fearful (or maybe we mean the same thing, but just use different words to describe it ). I absolutely agree with you, that he's very emotional and sensitive. All of these characteristics together (basically being a "herbivore" with a relatively gentle, defensive personality) can be seen as weakness and that sort of mindset certainly was a disadvantage as far as being an athlete is concerned (he always saw himself more as a performer with a mindset closer to ballet dancers or other stage artists than an athlete anyway and he wasn't driven by competitive results as much as by wanting to be the one, who got most appreciated by the audience), but also as a personal strength. He's always described as exceptionally kind, empathetic and considerate and is loved and seen as a role model by his teammates for it. It actually reminds me a lot of how Yuzu recently called Javi "almost too nice to be a competitor".
According to IK, who translated that interview on twitter. Pretty sure it should have been "as a result I tended to focus more on my flaws" instead of "their flaws". At least IK's interpretation goes against almost everything Daisuke has been saying in the past and the statement as translated makes absolutely no sense whatsoever unless Daisuke has a severe personality disorder. (Or maybe he chose rather unfortunate, ambiguous words in that interview.) As referred to above, one of his "trademark" characteristics has always been his self-deprecation. He's always been praising other skaters for what they did well/better than him.
Here he's praising Taka K. to the heavens:
And here he briefly talks about Yuzu/his younger rivals (from Friends+ with Shizuka in early 2013):