When it comes to balance, MMO's need to (and usually do) balance around a threshold, instead of "buff to the highest performer" like many players would like to see. Reasons stated in previous posts here, but I've seen the effect called damage bloat in a few Dev blogs. It causes things to either become too easy to fast, or the Dev's have to also constantly up the damge of mobs, resulting in huge inflations of numbers, and allot of extra work. It's far easier to just bring all classes to that threshold.

So the real quesiton is which class is closer ot the threshold. My personal theory is that BLM is more the standard for ranged DPS, and since it's underperforming by a bit, RDM will eventually see some minor nerfs in potency. outside of that, I don't know.