Fiddler2007; they are different programs.
RB is not BiaB. If you are content with BiaB that is great, but I always worry when people suggest they 'fix' RB to act more like BiaB ..
I worry one day that will happen and RB will stop being what it is.

Changing styles on a track in RB is easily doable, and many more variations can be layered, auditioned, etc.
It does many things much better than BiaB, but it is NOT BiaB, so yes there are some differences.
That doesn't mean RB is broke. Your statement that it is 'time for a huge set of fixes' implies that RB is broke.

There are trade offs due to the differences.

For my workflow I'd have given up on all the convoluted work to get a track to change styles in BiaB and simply generated different tracks to my heart's content in RB. Then sliced/diced the results if needed.

Like I said, they are simply different programs. Use whatever works for your workflow.

Make your sound your own!
.. I do not work here, but the benefits are still awesome