It would be nice to be able to add our own voice reaction sound clips like we can for team song.
You mean the Sound FX, and not the "Voice Reactions", correct?
The Voice Reactions can be customized in the VOICE area.
But yes, there aren't currently customizable Sound FX.
Basically, instead of having the computer voice speak what you type you have the ability to upload the sound files you want to play similar to how you have it setup for Team Songs. I do not find the computer voice very appealing. It would be much more fun to have ones own MP3 files to select from like having a soundboard within the fan draft software. Currently, I have to use a separate soundboard to achieve the comedy effect I like to have during the draft, but it is a lot to manage. Just a suggestion.