Hi skeezix,
Who knows, maybe some users need to get full control on the name of the recorded file (for some automatic batch processing etc...)
For instance if you choose a filename like "E:\temp\vlc_recorded_file" then you sure will know in advance what the name of the recorded file will be (not including the extension, which should be the same as the original video)
But if you choose a directory name like "E:\temp\" then the recorded file name will change on each recording (for instance "vlc-record-2012-09-02-18h15m02s-16-9 John Travolta & Olivia Newton John - You're the one.mpg") . That could complicate a further automatical process...who knows