I have 4 people I play with regularly that play DNC for one thing or another. True, DNC has to be on a mob for Sambas to be effective, while RDM can cast at least Enspell 1s from relative safety. It's just annoying that you can't get both to work at the same time or that a RDM/DNC can't apply both to an ally. I don't personally like the job combination at all, but I play it in dynamis so we have a raiser that can proc just in case a reraise goes wrong.