I have never understood what is so flat-out heretical about Bulgakov's "sophiology". I guess that's a topic for another thread though.
Mainly its origins and affiliations. At any rate, I wasn't thinking of Bulgakov's sophiology (which is comparatively more nuanced and ecclesial), but of Soloviev's, which is far more speculative and bizarre. Personally, I rather enjoy reading a certain Russian who wasn't included in this study, Fr. Pavel Florensky, whose synthesis of such Soloviev-like speculation is at least entertaining. Nevertheless, I sometimes have to agree with what Metropolitan Vitaly said about Florensky (which can also be applied to Soloviev, if not Bulgakov):
If one makes an analysis of Fr. Pavel Florensky's book with a pretentious title "The Pillar and an Affirmation of Truth" and of his other works then an Orthodox reader is confronted with an image of this outstanding priest with a turbulent soul who threw himself into the sea of theology without a compass and who is sailing towards a goal which is not known to anyone including himself. (http://en.wikipedia.org/wiki/Pavel_Florensky
It's all quite impressive and full of intellectual vitality and skill, but, what exactly, is it doing for the Church (aside from allowing us to showcase an impressive Russian philosopher)? It's certainly not representative of the Church's homiletic, catechetical or mystagogical traditions.
More generally, I personally find this school of Russian thought quite fossilized in time. Supposedly its thinkers are so relevant today (according to certain academics) because they adopted all of the questions and concerns of modernity and then tried to answer them from a peculiarly eastern and orthodox perspective (and are therefore better than the Neo-Patristic school, which is lost in the past and -- most importantly -- doesn't offer any amazingly novel or interesting insights into age-old questions). When I read these particular Russians, however, I see a bunch of 19th century questions and answers, most of which are indeed amazingly novel, but is that a good thing? Even if it is, we are still only left with novel answers to currently irrelevant dilemmas.
The Neo-Patristic school, however, has applied the Fathers' thought in all kinds of "hip" and "relevant" postmodern ways, e.g. the social Trinity, Patristic anthropology and human rights, St. Maximos and ecology, Trinitarian theology as a solution to the tension between the One and the Many, etc.
So, if Russian relevance falls by the wayside, what's left? Curious originality, which is certainly interesting and fun, but is it edifying and orthodox?
For Fr. Bulgakov, the patristic era is not static and closed, but rather endures till this very day; the same Holy Spirit that inspired the Father’s legitimate use of the rational and philosophical instruments of their day to better understand and define theological truths, continues to inspire the Church in this very day.
Again, I wasn't really thinking about Bulgakov per se, but, that aside: Simply because Bulgakov believed he was following the same Spirit, does not mean that he actually did so in every respect. The Neo-Patristic theologians of the 20th century define "patristic" in the same way (up to this very second), but they don't produce the same theologies. Thus, the only unique thing about Bulgakov is where his "inspiration" takes him (not that he somehow had an exclusively great insight into the continuing and Spirit-led nature of Tradition). Furthermore, according to his own definitions of sobornost
, Bulgakov's more speculative ideas have not been embraced by the Church at large and are thus, still, curious private opinions (at best). In contrast, one can't help but notice the markedly different reception which the hierarchy, clergy and laity (of all jurisdictions and even different communions!) have given the Neo-Patristic theologians.