RDM does look unfinished in my opinion. There are the reasons OP stated as well as the following:

Auto-Attack Dual Cast cancel: Your spells might not trigger an auto-attack, but your weaponskills will. So do you have to untarget-target the enemy everytime you use them?

Potencys: While RDM enchanted chain is really strong, thats more or less it. The potency of his "gauge fillers" isn't that high. As a comparison, watch a scholar video. The combined damage of DOT + Broil II is about is high as RDM normal spells.

So if you dont generate gauge, your damage will kind of suck. This means every dodge will cost you, every time the boss cant be damaged will cost you...

MP management: I quickly calculated, that even with perfect lucid dreaming use, you will depeleted in ~4 minutes. And no, you cant spam weaponskills as they cost 100 tp each.

To me the concept is great, but yes, RDM looks unfinished.