Mikhail Mikhailovich Bakhtin is the strangest thinker. As Michael Holquist writes: "The more we know about Bakhtin's life, the clearer it becomes that he was a supreme eccentric, of an order the Russian express better than we in their word čudak, which has overtones of such intense strangeness that it borders on čudo, a wonder. And this peculiarity is reflected not only in the strange history of his texts (why, ultimately, did he publish under so many names?), but in his style as well, if one may speak of a single style for one who was so concerned with "other-voicedness." Russians immediately sense this strangeness: again and again when we have gone to native speakers with questions about a peculiar usage of a familiar word or an unfamiliar coinage, the Russians have thrown up their hands or shaken their heads and smiled ruefully. Another difficulty the reader must confront is the unfamiliar shadings Bakhtin gives to West European cultural history. . . . Bakhtin throws a weird light on our received models of intellectual history" (Introduction to The Dialogic Imagination xvi-ii). Not only this, but "Bakhtin's motivating idea is in its essence opposed to any strict formalization . . . if you expect a Jakobsonian order of systematicalness in Bakhtin, you are bound to be frustrated. This does not mean, however, that he is without a particular rigor of his own" (xvii-iii). And I would add: his own sort of systematicity, that begins with a central idea and rather than continue to subordinate connecting problems and ideas, allows the essay to grow in strange unexpected directions (see the incredibly lengthy discussion of Rabelais in the Chronotope essay and you'll get a sense of what I mean - not irrelevant but somehow excessive, uncontrolled, undisciplined...organic).
So here's my (brief, incomplete) assessment. Bakhtin is proto-deconstructionist (a strong emphasis on alterity, multiplicity, instability, hybridity, context…and wow, see his whole book on Rabelais for some great deconstructive moves about birth and death and the earth and so on); at first he sounds wildly Hegelian ("Epic and Novel": the novel "com[es] to self-consciousness," the novel is a great step in literary development, worrying a lot about totality and expansion); but also sometimes sounds Wittgensteinian (context determines meaning, play, games; concerned about the "zone of contact" between the author and a text); obsessed with laughter and irony and the negative power of laughter (a little bit postmodern); Marxist (comments on class...divisions…alienation…labor...capitalism!); sometimes comes off like a proper Formalist (aware of the cycle of stylistic ossification...though he refuses to let the literary system live autonomously and is always looking toward the problem of mediation); a pre-narratologist (implied author, narrator, narratee, distances, etc. - at times he sounds like Genette or even Wayne Booth!), and finally he is a good historical structural thinker like Auerbach (but chronotope is a much more tenuous center to this whole than Auerbach’s thinking about interiority/exteriority, and what topics can be treated with what language). Is he even a little bit phenomenological? I don't quite see it explicitly, but Holquist suggests as much when he mentions presence, Husserl, and Derrida in the introduction -- apparently, also, the young Bakhtin was more thoroughly phenomenological, perhaps via his immense reading of the German idealists (see the IEP article linked below). (N.B. A friend tells me that Holquist disputes any Hegelian tendencies that Bakhtin may have, but it's not the dialogism that's Hegelian, it's B's entire idea of the novel, its emergence, and its tendencies.)
There's more, no doubt about it, but the resonances for his thought just in these four essays are all over the place. Where he's coming from, and where he's going - all of this is really vibrant, dynamic, perplexing stuff. I'm going to be coming back to this as I begin to write about style and Wallace, but I want to get deeper into Bakhtin's system besides that and understand more clearly the motive forces of his thought.
For more Bakhtin fun, check out The Internet Encyclopedia of Philosophy's article on the Bakhtin Circle at http://www.iep.utm.edu/bakhtin/