My issue was that I was changing *many files frequently which was causing MobileBackups to be created and indexed (and re-indexed), and well as causing the sleepimage to be updated and maintained -- this is different behavior than I had under Snow Leopard. The new behavior just uses a LOT more CPU and disk activity.
Once my LR Photo library was rebuilt, LR previews created, and metadata stabilized the CPU activity calmed down. This actually took a couple of days -- much longer than the system information of Spotlight indexing belies. Spotlight indexing takes about 10 minutes on my system, the other processes such as LR preview creation took hours and there is no indicator built in to monitor progress (I did it through raw Spotlight querying and watching the progress of the .MobileBackups (a hidden file)).
* Maintain ~10,000 images in Adobe Lightroom; specifically having new Lightroom preview files created, shadowed, indexed.
† I'm sure other large file repositories will have similar issues: Capture One libraries (especially with sidecar files since that effectively doubles the number of files), Music libraries (associated metadata, album artwork, DRM)