Plus it makes more financial sense to make good TVs that are affordable then to make high-end, expensive to produce sets that don't sell as much.
'Kuro blacks' is kind of a vague statement too. There have been several generations of Kuro Elite plasmas and all but the 9G+ Kuro Elites have been surpassed in terms of MLL. I don't doubt for a second that the ZT60 will at least match the 9G Kuro (or maybe even the F8500), but I'm not so sure about the 9.5G Kuro. With that said, were talking small differences here where only the biggest videophiles will care.
Some other areas I hope Panasonic to improve on, are with video processing, gradations/dither and susceptibility to IR. The VT50 already has reference color.