1) Sphinx search: the answer is "it is planned"
2) CDN: I use MaxCDN and would like to have an easy way to integrate that
3) APC, Memcache: the answer is they are optimized for caching
4) OpenX, Adsense, 3rd party ads system: I imagine it is not hard to have a things like "ads after first post", "forum home", etc
5) Spam prevention: are there any new features introduced to make fighting spam easy for site operators?