Walter Muir Whitehill always considered Bay State Road and most of BU, at least as far as the Cottage Farm (BU) Bridge as a legitimate expansion of the Back Bay due to the continuation of the Back Bay grid to some degree and the common Back Street seawall.
The Back Bay architectural style pretty much disappears beyond Granby Street, though. I think one or two 'Back Bay' buildings went up west of that before the whole development ran out of steam. They got absorbed into BU.
I was just trying to make a catty point, since Bay State Rd. is technically in Fenway/Kenmore.
But I would say Bay State Road is slightly unique. The presence of grassy lawns in abundance makes it feel much less hyperurban than the Back Bay proper. There seems to be slightly more variegation in the architecture as well - you don't see neo-Georgian on the other side of Mass. Ave.
An overarching design philosophy doesn't make Brasilia - or any development for that matter - work. On the contrary Brasilia was planned according to the most anti-urban of modernist design principles. Granted almost every major building there is a masterpiece compared to anything in CRP but in terms of planning it's autopia ad extremum.
Yes the townhomes in CRP look like CRaP. But at least it's added density and diversity and filled in space. It seems to be headed in the right direction - maybe one day they'll open the pedestrian pathways to traffic (which paradoxically would also increase foot traffic) and thereby weave together the area with the city.
Brasilia has no hope. All the energy is in the surrounding favellas.
Just because it's autotopia doesn't mean it isn't coherent or doesn't have a philosophy. It's beautiful in concept, it just produces horrible externalities.
A statistic that I don't know how to check: what is the population of the current Charles River Park compared to the former West End? CRP has fewer builidngs but much taller ones.