We got belted last year with Bailey at 5/8.
The first game when he came back from injury we went close to winning, and he would have been largely responsible. We were way under strength, had no luck during the game and the Tiges put on a couple of tries in closing minutes. Final scoreline did not reflect the game; and certainly not Bailey's efforts in the #6. I highly recommend you watch the bigpond video--round 13. In fact, I think you'll find the highlight reel alone will show him being the major playmaker for two of our best tries all season. (Neither from close to the line btw.)
He copped another injury two rounds later, and then finally came back into a team that was going through a terrible time. Badly depleted through injury and affected by the personnel shake-up and all the shocking publicity. And Bailey himself was reported to have been rushed back underdone out of desperation. And I still thought that he had a class look about him at various times.
I'm not saying he's a "playmaker" in the sense you might be referring to. He doesn't have the organising skills or versatility of Mullo. He's great at hitting a gap, he's got a step, a dummy, an offload and a great cut-out pass. Mullo's got other things like a kicking game of course, switches in plays and a variety of linking skills with outside backs that make him a complete 5/8.
If Mullo proved he could handle centre, I don't mind your idea of Bails in the 6 and Mullo out wider (coming in for last tackle kick options of course, as Pika mentioned). Dureau-Bailey do seem to have a complementary skill set.
I still think Dureau/Mullo is going to be our best option in the halves. But I think Bailey should be clear next choice at 5/8. And I do believe he should be somewhere in the top 17 even when all hands are on deck.