There are really two issues here:
1) the minor issue, which is that FARR's user interface should be more responsive even while searching deep directories. The problem is caused by unsophisticated use of multithreading that gets hung up waiting for the operating system to load directory information when it is out of the OS cache.
2) the larger issue, which is that when searching giant directories, for example if you have FARR to search your entire hd instead of just your start menu (the default is just start menu), then the fact that FARR does not index becomes a hindrance to use because it can take so long to live search those directories. An index would make such searches significantly faster, but brings with it it's own problems
I'd like to ask that we don't get into a detailed discussion of indexing and such stuff now, just because i'm not quite ready to think about it in detail -- i want to fix all my other pending issues in the next week or so and then we can talk about this again.