Standridge is only 20 and has potential to grow, but if we were imaging he was a 27 year old finished product, he would suck not because his gb/fb is 0 but because everything else is subpar. But as long as control gets to at least 75+, his splits will probably both be around 75-80 and P1-P2 should both be around 80, so he'll be fine.
GB/FB corresponds to ERA because double-plays are valuable in hitters parks. The fewer plate appearances with runners on base, the better. If your team plays in a pitchers park then gbfb matters much less