my $0.02 on the matter...
I think all champs should defiantly get their turn in the free champ spotlight. lots of good reasons for this have been covered in the last 102 pages.
however, people who have spent RP/IP on a champ need to have some form of precedence over the 'free' players. its better for the team to get an experienced player, less frustrating for those who have spent the time or money, and generally just makes sense (imo).
the best way (again imo) to implement this would be a simple UI change in champion select, for the first 10-15 seconds, only unlocked champs may be selected, after that point, the weeks free champs would be selectable. a simple cool-down animation over the free champions portrait, similar to the ingame abilities cool-down animation would allow new players to see that they needed to wait to select that weeks free champs. this would give players time to select their favorite champ, or the champ they just bought a skin for, ect..