I think we'll see a new iPhoto around the 10.8 release that includes a lot of the features from iPhoto iOS.
I think around ML release we'll see a new version of iPhoto that will:
- support creating and editing journals on the Mac
- Have the look and feel of iOS iPhoto
- Have the brushes and colors from iOS iPhoto
- Have Apple's map data instead of Google Maps (may be another reason for the delay if it's not ready yet)
- Have the 'show multiple similar photos' feature.
- Hopefully sync directly with iOS iPhoto
- Be built for 10.8 but support 10.7.4 minimum.
It might be optimistic to expect it to arrive with 10.8, but sometime in the latter half of this year, and definitely not before 10.8 is released.
At the very least, they need to update iPhoto for Mac to support the new "beam" feature for transferring photos (+ their lossless edits) to/from iPhoto iOS, and doing that requires that iPhoto for Mac support in its core editing stack all of the manipulations now in the iOS version. And if they need to support those features under the covers, they might as well also design interface elements to let you use them. So, a new iPhoto for Mac that offers something closer to feature parity with the new iOS version seems inevitable.
It's basically the same situation as exists with the iWork suite on iOS versus OS X: you can see where they're headed, especially now with the Mountain Lion demos of seamless sharing between the two through iCloud document storage, but they're not there yet. Mountain Lion is clearly the target point for bringing support for iCloud on OS X and iWorks for Mac into sync with the iOS counterparts.
