I prefer the previous version too. I miss the video editing tools and the ability to view a memory without background music.
But if you look at the new key features of improvements in iOS 15, most of the Photos features are about the Memories: iOS 15 - Features - Apple; unfortunately we have lost a lot as well.
"Photos. Memories: Apple Music
In addition to the hundreds of newly included songs, Apple Music subscribers can add any of the tens of millions of songs from the Apple Music library to enjoy on their devices.
Memories: Song suggestions
Apple Music song suggestions are personalized just for you, combining expert recommendations with your music tastes and what’s in your photos and videos. Song suggestions can even recommend songs that were popular at the time and location of the memory, songs you listened to while traveling, or a song from the artist you saw for a concert memory.
Memories: Memory mixes
Customize your memory by swiping through Memory mixes, which let you audition different songs with pacing and a Memory look to match.
Memories: Fresh new look
Memories has a fresh new look including animated cards with smart, adaptive titles, new animation and transition styles, and multiple image collages for a cinematic feel.
Memories: Memory looks
Inspired by the art of cinematography, 12 Memory looks add mood by analyzing each photo and video and applying the right contrast and color adjustment to give them a consistent look — just as the colorists at film studios do.
Memories: Interactive interface
Tap to pause, replay the last photo, skip to the next, or jump ahead, and the music keeps playing and the timing adjusts to keep the transitions on the beat. Change the song or Memory look or add or remove photos, and the adjustment happens in real time, without the need for the movie to recompile.
Memories: Browse view
View all the content from your memory in a bird’s-eye view where you can add, remove, or change the memory duration or jump ahead to another part of the memory.
Memories: New memory types
New memory types include additional international holidays, child-focused memories, trends over time, and improved pet memories, including recognizing individual dogs and cats.
Memories: Watch next
Memories suggests related memories to watch next after your memory finishes playing.
Memories: On-device song suggestions
Song suggestions are determined on device to protect your privacy.
Shared with You
The Shared with You section in the For You tab allows you to view photos and videos that have been shared with you in Messages. Photos taken when you were present also appear in All Photos and in Days, Months, and Years views and can appear in your Featured Photos and Memories, including the Photos widget. Save a photo to your library or respond to the sender in Messages.
Richer Info pane
Swipe up on a photo or tap the new info button to view information about the photo, such as the camera, lens, and shutter speed, the file size, or who sent a Shared with You photo in Messages. You can also edit the date taken or location, add a caption, and learn about items detected by Visual Look Up.
Faster iCloud Photos library initial sync
When you upgrade to a new device, iCloud Photos syncs more quickly, so you can get to your photo library faster.
Limited Photos Library improvements in third-party apps
Third-party apps can offer simpler selection workflows when you grant access to specific content in the Photos library.
People identification improvements
The People album has improved recognition for individuals.
People naming workflow
Correct naming mistakes more easily in the People album.
Selection order in the Photos image picker
The Photos image picker, including in the Messages app, now allows you to select photos in a specific order for sharing.
Suggest less often
Tap Feature Less to let Photos know you prefer to see less of a specific date, place, holiday, or person across Featured Photos, in the Photos widget, in Memories, or highlighted in the Library tab.
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