Concept sounds interesting, like a different take on the Populous style, but... wtf is this? Poor pc controls (smells like bad console porting)? Internet connectivity required? Oh, Ubisoft. Ugh, no thanks.
I didn't get it either; if you grind, your BR WILL rise, and you're screwed. Plain and simple. What they PROBABLY meant was like later on in the game, return back to easy areas, and THEN grind on easy monsters (for skills). BR doesn't affect skill gain iirc, only monsters' BR.