I was researching the new features that Sitecore 7 will have and I found out that there will be lots of features for developers.
Among other things, Sitecore 7 has been rewritten to leverage .NET 4.5 API. It has also updated third party libraries to the latest version and it has a new implementation of the Item class. But the biggest improvement IMHO is in their search. The refactored search and index architecture allows you to:
- Plug search providers, including Solr.
- Tweak all Lucene settings through Sitecore configuration.
- Use the new Crawler API.
- View reindexing statistics right from Sitecore Desktop.
- Rebuild part of the index, not all the index.
- Clear HTML cache on index rebuild.
If you want to read more details, you can take a look at this blog post Sitecore 7 Peek.