I have nothing against members of the community coming up with ways of making editing more enjoyable (with the motive of making it more frequent). That happens already, in some of the ways you suggest and in others you haven't imagined.
But it is important to remember that these incentives will be aimed at getting people more active at reviewing sites that surfers think should be reviewed -- and this will not necessarily serve any particular webmaster's purposes. An incentive to serve a particular webmaster's purpose, is called a "bribe", the offerer receives the disincentive of a permanent place on the Hall of Unspeakably Unlistable Shame, and the recipient receives the disincentive of removal of editing privileges.
In practice, this disincentivizes many incentivatory schemes proposed from outside.
But it is important to remember that these incentives will be aimed at getting people more active at reviewing sites that surfers think should be reviewed -- and this will not necessarily serve any particular webmaster's purposes. An incentive to serve a particular webmaster's purpose, is called a "bribe", the offerer receives the disincentive of a permanent place on the Hall of Unspeakably Unlistable Shame, and the recipient receives the disincentive of removal of editing privileges.
In practice, this disincentivizes many incentivatory schemes proposed from outside.