The focus on rDPS is entirely a reflection of player demands on this forum. I wouldn't be surprised if you could draw a direct correlation between job iterations that were considered 'badly designed' and 'weak' and the existence of an rDPS deficit. Players are more likely to forgive a 60 second recast difference on a defensive than they are to forgive a 60 rDPS difference. PLD hasn't really changed its playstyle, it's just moved to the lower end of the rDPS scale for tanks. DRK sat in the exact same spot (with an even bigger deficit) for two expansions in a row. It played out the exact same way.

I think feedback from these forums would be much more effective if people here simply dropped the farce and acknowledged that everyone and their chocobo wants more rDPS. Just give everyone in the role rDPS parity, unilaterally reject any 'difficulty'-based claims for advantages, and let the discussion shift to variations in playstyle and utility. Those discussions are much less clear cut, and you can actually have some unique trade-offs. Mobility cooldowns are an excellent example of this.