I'd complain about neither of those things. As a Paladin, I already know about getting both parts of my weapon set.
You fail to understand that the reason it was phased out was for this very reason. I for one, as someone who has played WHM since the beginning, am very happy they phased out one-handed/shield combos; it was superfluous, annoying, and added nothing to the class besides more hoops to jump through for upgrades compared to SCH (and now AST).

I like the additional option and flavor that brings to the class/job. It is a distinction and part of the identity IMHO. This is the thing that you and others don't seem to get because you are totally focused on performance and comparative analysis of performance, especially in end-game situations.
It would change absolutely nothing about how the class is played. Not one thing. Your chief complaint is that WHM isn't a special enough snowflake; how would being able to use a different visual for weapons change your complaint?

WHM is different from AST/SCH because it doesn't have gimmicks to fool around with while healing. If you want gimmicks, play a class with gimmicks. WHM is fine without them and is the better for it.