Personally I'd rather have a few people running around on a pointless setup if most people can make a fun, unique, and useful setup that is a defined role at the same time and as you said you don't see people running around as DRK/BST then probably you won't see people running around as DRK/pet class in FFXIV. So would you have SE remove sub jobs from FFXI so people can't have choices like PLD/WAR to PLD/BLU or RDM/WHM to RDM/SCH just to eliminate the possibility that someone could go DRK/BST. If not then why deny adding practically the same thing to FFXIV. IMO more customization = more fun, however it is harder to balance, but if it can be balanced, roles can be defined, and uniqueness is present then in turn it WILL be more fun.

As for gear yes that needs rank/class requirements and as for using wide volley with an axe I don't know what to you other, but either way this thread's proposal doesn't make this worse.