Based on a discussion on the dev list, it would be interesting to provide a dry run mode for the indexer which would give an indication of an average indexing time.
Input could be:
- path to index definition (mandatory)
- path to the content (mandatory, default could be /)
- max number of nodes (optional, but I'd still cap this value so indexing doesn't take over the entire aem instance)
Also, we could do this on a separate (dedicated) thread so it doesn't interfere with existing indexers.