>Yet single clicking the home button still instantly gives you the response you expect.
The task manager/switcher is a child of the home screen. This overloaded functionality makes sense that you go to the home screen immediately and if you happen to click again it goes to the secondary mode.
Vlingo on the GS II has nothing to do with the home screen. It is its own world.
Should they have made the very first click instantly go to the home screen anyways (which could involve a lot of busy work given how rich an Android homescreen can be)? Good question. I don't think the two are directly comparable however.