It looks good, but there are a few problems, mainly due to line length.
The , , and are already very long lines that suffer from erratic service, and an extension will only worsen the problem. However, we can't really fix this issue without doing some wacky service proposal.
The RBB should be built off of the Queens bypass, not QBL. Putting it on QBL would limit capacity there and the , being a local, would not attract many riders.
This is more of a question, but where would you put the new NYTM? The only practical place I can think of is City Hall LL.