I don't support the Bulls.
I'm picking Swepson because I prefer having leg spin as the slow bowling option. His FC average (34) is currently better than Lyon's was when he was first picked for Australia, so I don't see the issue. He is showing that he is improving whereas we pretty much know Lyon's ceiling and that he's got all of two different deliveries which are variations of the same ball with flight.
As for Renshaw, I just think the Big Bash has been a large factor in his demise. Too many technical changes and he was torn from pillar to post about his mental approach and shot selection. Moving him around the order hasn't helped. I think if he was to focus exclusively on red ball cricket (like Pujara does) he could be the ideal opener that just soaks up pressure and bats time. I saw enough in India to suggest there is a player there and he's still just 24yo.
I would like Renshaw to score runs in shield before he's back in the side and I accept there's no argument that he should be there on form. I just think there's no real option at #5 that is in-form either and I don't see Pucovski as a long term opener, but it appears that is just me.