FT2232HL interface board critique
Looking briefly at the layout, it looks OK. You seem to have generally followed the advice. The following are things that I would do differently, but are not actually problems with your board:


I prefer to err on the side of thicker tracks, especially on a board with this much free space. E.G. For most chips, I would make the tracks as thick as the SMD pads.
Where decoupling caps connect to chips, I like to make the tracks as thick as the capacitor pads. Sometimes you need to use two or three tracks in parallel to achieve this.
I tend to spend a couple of days fiddling with the board, tidying up tacks, pushing things around, making things symmetrical, especially where crystals connect to chips. I like to make those perfect if I can. No reason, I'm just anal.
I think the bottom side can be tidied up a little, especially under the main chip. Some of the tracks there are taking quite indirect routes.
One last word of advice. Check and check again all of the connectors. Check that you are using the correct gender, and that everything is the right way round. Even after laying out PCBs for more than 10 years, this is still something I get wrong.


Aside from those, I don't immediately see any reason why it wouldn't work. The length difference between the USB data lines is probably too short to be a problem. I haven't used USB before to know.