Design og the GS650 is based on making it a more on-road bike, with the possibility of steping out to the dirt (fair) with no big complications.
Dakar makes it harder to sneak fast on twisty roads.
If you make those changes you comment you will end up with a purebreed hybrid that will do not so good on both conditions.
It is all a matter of compromise, nothing is for free.
I will clear up my mind exact in what I really want to get from the modification and then try it.
If you do it, please let me know how it worked.