The homes we were looking at had huge lots, but you could not use them for boat or RV parking and we wanted a true 3 car garage, not a tandem.
Blackstone might be nice for empty nesters or a new family starting out and the schools and kids are able to be built and grown over time. For us in the middle it was just not the right fit.
[Edited to address just a couple of points]
You're absolutely right, due to the sloping terrain in Blackstone, the large lots give great views but do not typically accommodate RV parking. In fact, based on my recollection of HOA rules, RV parking isn't allowed unless it's concealed from the neighbors. Our neighbors with RV-type vehicles rent off-site spaces to park them.
However, many homes have proper 3 or 4 car garages -- so it depends on which floor plan and builder you choose. Don't get me wrong, there are plenty of tandem garages too. There is just a lot of choices available -- in fact the one rare thing to find in Blackstone is a 2-car garage.
And you're also right about the empty-nesters. I would argue about 50% of the residents (depending on neighborhood) are retired or have adult children. Mostly bay-area transplants. But there are tons of kids in Blackstone too. I have serious doubts about the school district's population claims vs. what I can observe.
That said, as mrbrenan points out, the views and sunsets are spectacular. Every time I drive to the office and see the entire Sacramento valley in front of me, or drive home and see the hillside with oaks, cows, and rabbits hopping around, I realize we have benefits that our previous neighborhood in Folsom could never offer.