I think this is much better.
However a few things I notice:
- Is there a reason you have the large plate on top of the frame rather than below it? If there isn't a reason, you could probably move it below and protect the electronics a little easier.
- I would recommend that you try to support the gear box output shaft on the end.
- I would also only make the shafts 1/2" hex at the wheel. By turning it down to regular 1/2" you save yourself the need to purchase a broach. Additionally you can save money by purchasing regular 1/2" bearings ($7 vs $9.50) rather than hex bearings.
Again, this design is much better now, good job.