Yep they are definitely vehicle first, robot second when it comes to design. As a collector of both Joe and TF I would love to have a better robot mode, but in the end I'll take an accurate vehicle mode over robot mode. However that doesn't mean I don't was a sensible robot mode. I would hate for them to do a great vehicle, only to have the robot look like hot garbage.
Now, granted, there is only so much they can do when they have to marry two existing forms into one toy. There will inevitably be some corners cut to make them both work, but so far they have done a pretty great job. Plus they have to make the vehicle modes hold figures on top of everything else!!! I would imagine if the designers had to start from zero there would be a much better marriage of the two forms, especially if they didn't have to worry about trying to fit 3.75" figures into the vehicle modes as well.