Hi. I like it, although it could use some changes.
For me personally, it's a bit boring.
Shouldn't be, E major isn't that hard on string instruments
Yes, this is where I think the majority of the changes could be done. The first half is slow and not moving much even in the viola and I think that's on purpose. One thing that I think can be changed is measures 25-30. I like how the cello becomes more melodic here and less of a bass, but I think this could do with low register viola as a bass, that way the cello gets the spotlight for a few measures. Don't get me wrong, the high register viola you have there is great, I just think it could do with the cello being highlighted in measures 25-30 and the viola being the bass in those measure, you know, for the purpose of contrast. I do this interchange of melody and bass myself in my own Duo Sonata for Violin and Cello.