I am not a fan of Rob Simmons because his general play is really not up to international standard. He has one particular skillset of managing and winning lineouts, but even there in recent times he hasn't shown any margin in skill or results over other options.
I'd prefer to see the likes of Douglas, Arnold, Coleman and Staniforth become our go to locks for their greater impact in general play.
Ah yes the whole general play and dynamism argument, it gets rolled out at Wallabies selection time ever 12 months. Asking for more dynamic play from Simmons in general play is like asking for more set piece refinement from players like Coleman and Arnold, they are both weaknesses in each others game.
-Simmons lacks in general play, that's not going to change, his strength is without question his input at the set piece.
-Arnold's impact is in general play, Arnold needs technical refinement in the set piece, raw physical potential but still leaning the technical aspects of the game, error rate is still to high for a test lock.
-Coleman has been completely outclassed every time he has gone up against a first class lineout opponent in Super Rugby, he is still young and learning. Long term he has a lot of promise an is potentially a long term Wallaby option, just needs more time to learn the ropes.
-Carter, needs to rediscover his 2014 form, until he does he shouldn't be in the Wallabies.
-Skelton has no place in the Wallabies until he improves his fitness and Cheika increases the lineout options in the forward pack.
-Douglas, he is probably the most balanced of Australia's locks, good work rate in general play and the set piece, but exceptional in neither.
Australia's lock selection isn't a matter of ranking them 1-10 and selecting the top 2.. It's about finding balance In the squad, whilst Cheika continue to run 2 open sides Australia's lineout will always be marginally worse off then countries like New Zealand and South Africa who have 4 jumpers.
New Zealand is also the best defensive lineout in the country, this will forever be a selection consideration for Bledisloe matches. You can't hide from lineouts, Australia tried in the RWC GF and England Test Series but failed badly at it.
My preference would be a lineout partnership of Douglas-Coleman, but like alluded to above I'm not sure Coleman is at the leve required yet.