You don't want tracks to be normalized - it removes dynamic range originally intended to be there by the producer. Besides, if people complained about how long it takes to analyse a track for the waveform, could you imagine how PO'd they'd be about the processing time for analysis and normalization?
As for auto-gain, if you're simply playing tracks, why not use another application to do that? The purpose of rekordbox isn't to play your dinner music.