Looks really great! I love the foreground plants! The rock looks a little off-balance -- maybe have a taller stone back behind the right-hand plants, or group the stones off to one side or the other, or center them for a strong focal point. I'm anal about stuff like that, though, so it could just be me. :-) Gorgeous job!
This should be real nice once everything starts growing. I think placing the rocks together as giant boulders would greatly increase your focal point. This has a potential to be a James Findley if you go with a higher slope. Then put some type of moss on the rocks for depth-scale. Overall..this will be awesome.
Tank looks great, but I do agree with the height in the back needed comment. Maybe some hairgrass or stems? Btw, with the S. repens, exercising good maintenance principles by trimming it down when it gets taller will make it grow back in healthier and denser. You can see the effect of this in plantbrain's 180g thread.