Well, overall, it's a good looking image really, in a classic colour palette, nice
Yes that amount of exposure does seem to suggest a little more faint stuff should be visible, maybe longer subs..?
Just for comparison re depth,
this is 2hrs worth of 5min subs with my FLI Proline 16803 and 12" F3.8 Newt and a 12nm Astronomik Ha filter, in what was the usual crap seeing (at 1.6"/pix), from light polluted inner suburban Newcastle.
Mike