My experience with ABS-type balls is similar to what you describe - the drop in spin, and the difficulty in applying spin vs the reward, results in the most efficient route becoming to concentrate on another approach. I feel that it's one that reduces the focus on over spinning the opponent, and moves more towards taking the ball early and countering with precision and power. I still find that I can get better results with seamless (I can induce a lot more errors via opponents blocking heavy topspin off, for example), but with the harder-feeling ABS I find that any topspin I send out with any height can just be hit through, for the most part. It's a much riskier strategy than it used to be.
Looking at Niwa v XX, I thought Niwa was taking enormous risks on counters, right from the start. He was aggressive to the point of recklessness, and I thought there was no way such a low-percentage approach would work. But he started to land a few (and they were totally ridiculous - proper all-or-nothing shot selection), and I think it spooked XX. XX relies on application on heavy spin on the FH wing more than most, but wasn't allowed to rally, or even to get to a position where he could start to vary his spin. Niwa took it away from him, and XX didn't have a plan B (or wasn't comfortable applying it against Niwa, who was peaking). And quite apart from XX - Niwa landed some incredible counters - I genuinely LOL'd at 2 or 3 of them because they seemed wildly optimistic, but were just perfection. That is some performance, take nothing away from it.
I don't think this comes down to ball consistency as such - I think the NP40+ just favors a specific approach to the game, and gives a slight disadvantage to players who have big swings, or play further away from the table. Close-in counter players will feel a bump OTOH. Sure, the ball is the same for everyone, but not everyone will adapt at the same rate, and some players would have to jettison major parts of their game style. Someone like FZD comes into this almost ready-made to suit, but players who rely on spin more feel the impact. I thought Boll would struggle with any plastic ball, and I can't see wider adoption of NP40+ or D40+ helping his cause, but the lack of cut-throat competition pushing from below in Germany has kept him relevant on the national scene. XX does not have that luxury - will he be given time to adapt, or would it be better to concentrate CNT resources on other players with a more suitable playing style? I don't think he will be given much more time if he continues to struggle, but it's only one result in a pretty non-standard tournament, so there is certainly no trend. Just speculation.
I don't look forward to watching some future match-ups of the same close-in style in the men's game though. Lots of points where a kill is attempted on the 2nd-5th ball, either landing a winner or missing by 10 feet. Not the most interesting type of game to watch.
I don't mind admitting that I thought the abs ball would totally play into the hands on the CNT women though, barring DN. Here you have the quintessential close-in playstyle at work. Instead you get the emergence of Miu, who looks to have found a way to apply a sense of abandonment to her close-in work. She throws a lot of everything into her shots, and I'm amazed by her ability to recover more than anything else. The CNT players look serene with their short strokes, but Miu brings the blitz. A savage whirlwind. And her serves are very difficult to attack hard - she gains the initiative very early. Can she play at that speed and level for best-of-7 though?
If nothing else, these are interesting times.