In my town, all I see are RX350's, S550's, SL500's, 3er convertible, RR, RR sport, X5, X3 etc, but rarely 7 series. BMW needs to speed up the redesign.
As far as people calling the E70 a soccer mom car, don't say that until you drive it. A lot. I thought the size of my E53 was perfect, and when I heard the new X5 was going to be longer, I was throughly turned off, and started to look elsewhere. But, after test driving it for a long time I decided it drove much like the E53, and you don't notice the size at all except for maybe parking. While the X5 isn't as raw, it sure isn't a soccer mom mobile. I continually carry a lot of passengers and a lot of cargo, and I never realized how tiny the E53's cargo area was until I met the E70. Now, almost every other time I'm in the X5 all five or four seats are filled and the cargo area is full. So, after growing several inches, I have more room for stuff, while having, IMO, a better driving SAV.
Honestly, I can't see BMW selling a single X6. Who (besides L) really needs a 4-seat MB R class that's high off the road, and high in price?
As far as the X3, sure there's a big(er) gap between the X5, but why do you need to fill it? Then you're back at E53. Then they'll want 3 rows. (*cough Toyota Rav4 cough*) I find that the X3, while it does have a small cabin, does not need to grow drastically on the outside. Just utilize that interior space better, like shaving a slice off the cargo area, a bit off front leg room, maybe make it a bit wider, etc.
Just my $0.02