Well, he probably will. The Wallabies results in the last couple of years have been distinctly better when he's played.
I agree that Simmons is a better set piece operator but Coleman is comfortably our best overall lock.
I think Simmons form this year has been on par with Coleman if not better. He's shown a level of physicality that he never showed with the Reds. I hope they both play.
Whilst Rodda, Tui & Arnold are great players; if we're going to go in with two 7's and an 8 who rarely jumps we need our best lineout operators on the field. The lineout success rate (and spoil rates on D) are comically different when you compare teams with Simmons and without Simmons.
Rodda & Tui's development have been severely hampered by having a coach who was never much of a lineout option. They're just too slow across the ground.