Don't worry about the fluid block, it's one of the first unecessary gadgets developed by BMW on its production, before it became a rule today. Remove it if you have to change the pivot bearings, it won't change anything.
No particular weak points on K75, the torque is less important than on K100 so spline issues are not common.
Check under the waterpump to track oil or water spill, idem under the clutch carter, pay attention to the disc brakes thickness, check the good function of the clutch.
The fuel pump must not be noisy -except if the fuel level is very low.
I drove many of them, repaired much more, even the worst frenetic cops could not break them, they needed to hit something concrete to kill them.
It's probably the more reliable bike BMW ever made.