Please include conversations in Search All results. As it is now, you have to do a separate search to conversations in order to find the same term everywhere.
Conversation Improvements is what provides conversation search results.
Conversations are in all search results, it is likely they are just being pushed down by all the other hits. You can adjust the search weight options via Search Improvements to show up as more relevant hits. It will require experimentation to find the best search result weighting
