Disagree, -1 to the many +1's on this.
If you would be running Reaper 1 at level to get full XP but are 2 levels over at BB then run Reaper 2 and your extra levels will probably make it easier and about the same XP because of scaling. I like that it encourages doing things at levels where they really are extremely hard, and I'm happy taking an xp hit if I can't handle it at a lower level.
I would recommend cutting the 50+... to be more like 10+... to make the scaling more linear, increase the multiplier by a fraction to compensate.
If you remove the stupid awful power creep trees that nearly everyone hated on first sight when unceremoniously dumped on us, and still hate even as they hopelessly chase after them, and replace them with something less power creepy (tree of only shared-timer clickies of various kinds you can fill out slowly gaining extra charges as you do), and an eternal ability to gain tiny amounts of hp/sp as gaining reaper xp, then by all means expand it to bravery bonus size. The trees continue to add a horrible taste to what is otherwise a real success in Reaper. Serious fail.
Or just shrink bravery bonus levels to match reaper bonus xp if that will make everyone happy that the grouping incentives are aligned... (...don't really do that, but it's where the corrupt-a-wish logically heads)