I'm OK with the 17 and the 19, may even like them more when I see them in the flesh, but I still ain't feeling that 18. I have the 8000's, and to my eye they are much better balanced. If I were going to change the 8000s, I would have tried to maybe make them a bit taller, a tiny bit larger in diameter maybe, with smallest form factor electronics possible (maybe even put in the base) to allow another bass driver optimized for low end to extend their range a bit. Maybe have an ALT sticking out of the fabric where the tweeter is now, not stuck on top like an afterthought.
Still, to my eyes the BL2 and BL4000 are a bit better looking and more well matched to the other speakers in the old BL line. They say the 17 has a coax driver? Tweeter over the woofer? Interesting, shades of Tannoy.