Well, this particular example would be apples and oranges, because my Casio CDP-200R has weighted keys, not synth/organ style keys. As a weighted-key model, it is very good. It is, in fact, graded hammer action. I haven't seen it advertised as such, but there is clearly less force required to play the higher-pitched keys than the lower-pitched keys.
But for my limited experience with the newer Casio portable keyboards with non-weighted keys, I definitely agree with you. When I play them in a store, they feel kind of "springy" and "spongy" to me. The newer models seem better than the older ones, but in my opinion, nowhere near as nice as the key feel on my PSR-E433, or even the newer models like the E463, which, as we've talked about on here before, has a slightly less satisfying action than the E433.
It seems that Casio is trying to get a semi-weighted feel to try to simulate the feel of a piano in a portable keyboard -- including the waterfall style keys -- but I don't think it really goes over very well. They should just go back to a good, solid synth/organ type feel for portable keyboards. Interestingly, on their website, they are getting ready to introduce some new models, including a CT-S 400, which seems like it has many of the features of something like the PSR-E433, but without live-control knobs. I don't think it has filter and envelope controls, either, but I'm not sure. It will be interesting to take a closer look at it, but of course, I can't imagine replacing my PSR-E433 with it, especially if it doesn't have filter and envelope controls.