It should be part of G+, because it's cool and google usually does cool things. But it is indeed useful only for the top % of users, because the average user doesn't get that many reshares.
PS: yes, I would really love to be able to build apps/games for G+ the same way I can for Facebook. If G+ would do that I bet developers would jump on the opportunity. It's going to be like .. Android vs the iPhone all over again
Instead, empower the App developers do such awesme innovation with your data. <yegge_repeat> Learn to think like a PLATFORM! </yegge_repeat>