BLIND usually playing as my left D winger (the other side of DE BOER).It is very much possible to have DR/MR/AMR, but he will be less effective. I try not to mix defenders and attackers.
He has better defending skills than DE BOER but the rates and the contribution to the team are about the same
BERGAMP usually playing as AML. Also his attacking skills are better but the rates and the contribution to the team are the same (if DE BOER was playing all the time as AMR).
I really don't see any difference in balanced skills and increasing (relative to position) skills.