The movement does contain a lot of good ideas and shows promise, but I have to agree with Chris for the most part.
I have listened to it a couple of times so far and even mapped out an approximate timeline (though the exact times may be a little off since by the time I read the counter it may have been past the point). I would say first that 11 min is not necessarily too long for such a movement, but as Chris points out it needs to have more dramatic impact. As Chris points out, you start a build up at about 7:48 that lasts to about 8:30. Just before this point I hear the movement towards a climax, but it never makes it over the top.
At 8:08 you start an idea that seems to be initiating the climax, you repeat (slightly altered and reaching higher) from 8:13 - 8:16. this idea needs one more repetition. (BTW, that is one thing I have noticed about some of your previous works is that they seldom go for a third repetion of an idea in sequence or altered). This point of almost climax is appropriate in proportion to the movement -- about 2/3 of the way through. Consider that if you were to start the build to climax at 7:48, that you could do it in 3 or 4 waves, for example the first wave builds from 7:48 to 8:08 (8:08 being the crest of the wave but not the big one), it could then back off (but not to the same level as at 7:48) and build to a higher crest from 8:08 to 8:13, it again backs off and rises through your point at 8:16 to about 8:20 [if this is to be the climax, you could actually extend the ultimate climax by dropping back further than at 7:48 and making it build much more, such as with 3 or 4 repetitions of the idea or extending the time from low to high in each waves crest.] (I hope this is making some sense).
After the climax, it is common in a sonata form mvt. to have a long dominant preparation, incorporating a dominant pedal.
On a similar note, between 3:43 and 4:25 (and similar spots), you begin to incorporate syncopated violin descant. Each time this ends prematurely. Though not restricted to it, this change from quarter to syncopated quarters was often used as a device in the classical symphony that Charles Rosen refers to as "Rhythmic Modulation" (it must be his term since I can find no one else who talks about it as such). The idea is that it is a means of quickening the pulse rate of the music without actually changing tempo. Classical composers would often use this device to create movement on a static harmony to build excitement. I've attached a very basic representation of the idea.
Rhythmic Modulation-1 (scaled 2).png
Essentially what the composer is doing is that each time he introduces the syncopation of the previous unit, he prepares for the next shorter unit while maintaining the same number of attack pulses as the previous unit.
Here when you began that feeling of the syncopation after the regular pulse, I expected to then hear a further quickening. It is also related to the earlier idea of repetitions or sequences in threes -- a three phase movement of ideas.
Did you repeat the exposition material (either through an exact repeat or even through variation)? It wasn't clear to me that you did. Though not an absolute requirement, I do believe that in most cases the repeated exposition is important to the form. It first helps us to know the "players" (the themes) in the piece. It also helps to establish the overall key-ness of the piece. In sonata form, though we say a piece is in a particular key, G minor in this case, until the recapitulation, more of the piece is in anything but that key. Thus the repeated exposition helps the listener to establish a firm grounding of how all of the other key centers of the piece relate to the goal of returning to tonic.
Also, the repeat of the exposition often allows us to hear the initial musical ideas in a new light. A couple of Beethoven examples come to mind. His 5th Symphony is said to be in C minor. We know because the title says it and the key signature says it, but look at the first 4 notes: G - Eb F - D. As music students we dutifully analyze this as [cm:] i V. If we did not have all of this information, why is it not in Eb maj? G - Eb is the lower 3rd of I(Eb) and F - D is the upper 3rd of V (Bb). It isn't until the repeat of the exposition that we have the opportunity to fully hear these 4 notes as C minor. In the "Waldstein" Sonata (op. 53) We are told that it is in C major. It starts with that repeated C major chord followed by D7 and G. In C major, we dutifully analyze this as I V of V V, but it is also an authentic cadence in G - IV V I. The next gesture in F is heard the same way IV V I. (Granted the juxtaposition of the G and F triads are good indicators of C major, it is ambiguous enough to keep us on our toes. And to top it off, the first utterance of the theme ends in C minor! It is not until the repeat that we have the opportunity to hear these initial gestures in C.
The sonata form is by its very nature a dramatic form built on tension and resolution, repetition and contrast on many levels. One level may be creating a tension while another concurent level provides release. All of this builds up to a climax and all of the un-resolved tensions are finally resolved in the recapitulation (and coda if necessary). These were more likely the thought processes that the classical composers had rather than saying that the were writing a "sonata form" movement (the term wasn't really used until the 19th century after Beethoven's death.)
Anyway, just some thoughts and some things to think about.