Forgive me if this is what you're saying, but the B6 will actually lose out on two HDR standards: Advanced HDR by Technicolor and HLG. Looks like all other models in the X6 series will be upgraded to HLG, but the B6 was conspicuously absent from the announcement. Probably because of the different SoC than the rest.
Will it matter? Who knows? Standards war, yay.
Normally, I'd say wait and see for pricing and reviews on the X7s, especially to see if there have been significant improvements in motion processing, shadow detail, and uniformity (which, depending on your tolerance, could still be an issue with the X6 line).
But as I mentioned before, there has been at least one retailer on AVS Forums who said the X6s basically sold out over the holidays (in the US), so remaining inventory could be limited. Keep in mind that's one retailer, but it's a fairly respected one (Cleveland Plasma).
Me? I'm waiting. I think there will still be enough X6s to go around if the x7s don't live up to the hype. But while that's a risk I'm willing to take, I'm not sure I can comfortably recommend others to do the same.