Mate, you need to change the meds. Hilf bowled tidily enough (I assume you mean WACA not Gabba), but the reason we took 20 wickets was firstly Johnson rediscovered line and length at the same time he rediscovered inswing, and secondly Harris was in the side to back that up with some quality bowling. Hilfenhaus cannot continue to fail to take wickets. Copeland for one can keep it just as tight, but also gets em out. A bowler who doesn't take his fair share of wickets very soon finds themself out of the team.
If Hilf leaked runs and the strike was able to freely and regularly rotate when he bowled, a lot of those wickets wouldn't have been taken.
He kept one end tight, restricted runs, and soon enough the poms started to feel the pressure and started to chase runs. Knowing they couldn't get the runs off Hilfenhaus they looked for opportunities which weren't there against the bowlers at the other end, and consequently got out.
I'm not taking anything away from Johnson and Harris' bowling, it was great and where it should have been from ball one of the first innings we bowled in this series.
I wouldn't remove Hilfenhaus, Siddle proved to be more erratic, couldn't get a wicket and leaked runs.