Andy summed this match up exactly - "Today there was nothing. There was no atmosphere 'cause there was no points. That was it."
It wasn't even a decent practice match and Andy did well to only lose his focus a couple of times, but brought it back very quickly, which was encouraging. According to the BBC Kukushkin pulled out citing a left hip flexor problem. Possibly he had but I suspect fatigue and the scorching heat (37C/98F on court) had more to do with it. Very good for Andy of course from an energy-saving point of view, especially as the hot weather looks set to continue, but he knows that he cannot let things slide, and Lendl and the team will certainly ensure that he keeps himself in good shape.
The worry I have is that Andy gets rid of Novak only to have him choke in the final yet again with Nadal or whoever taking it. I will have a lot of problems living with that.
If he does get through Nishikori & then Novak all of this no British player for a 100 years rubbish better be put to the side. He's a big boy now, there should be no excuses.
I share the same concern because I fear that that Andy still isn't up there mentally enough yet to win a Slam, and he'd have the added problem of overcoming the spectre of his last two final defeats. He's only been working with Lendl for a very short time and, although already one benefit has been seen, i.e. his on-court attitude has improved and sharing his frustrations with his box has stopped, I seriously doubt that this will have been enough for this particular psychological problem to have been sorted out.
However, as to the rest of your post - I don't recall Andy ever making excuses for his poor showings in any match, and he certainly didn't after losing these finals. Yes he's matured a lot, but, as I've already said, I think he does have a genuine mental hurdle to overcome, and one which isn't peculiar to Slams either, and that isn't likely to vanish overnight.