1) The bread crumbs above could be made expandable and Home pointing to the dibo index could be an alternative?
2) When I am quick replying to a thread, the "+Reply to Thread" button still stays and I tend to click on it rather than "Post Quick Reply". This resets the "Quick Reply", which I found irritating.
While I may get used to this gradually, new users would be unhappy with this approach.
I don't understand quite what you want but the bread crumbs still seem to work as before with Discussions being the Discussions Index page.