I'd ditch the DB9 and use a header. You can get IDC DB connectors that use ribbon cable so they still look neet and can easily be mounted remotely, makes fitting the board into an enclosure easier and you can swap from male to female without desoldering a connector.
That should route easily (manually of course :)), using the DIP doesn't really make it worse because you can run 2 lines between pins, whereas the TQFP is basically a no go zone for one layer.
Please get rid of the huge USB connector and use a mini B.
Add a jumper (not a solder bridge) for the auto reset so it can easily be disabled.
The headers at the end of the chip are pretty close, Ok if you use a screw driver to remove the chip from the other end but may get in the way of a chip puller.
Crystal too close to the chip, especially with a socket.
I'll shut up now, I guess it's just a quick mock up but thought I'd highlight a couple of things anyway.