Deezer shuffle mode does not really play songs in a playlist in a random order. In playlists I have songs that are never player, and songs that are played every time. So somehow songs get weighted and the playback follows some kind of heuristic or pattern.
Whilst this may be ok for some people, my guess is that most people don’t wan’t to hear the same songs over and over again but all songs in their playlist with the same probability and truly random distribution.
So in my opinion you should at least provide us users the option to choose between those two shuffle modes.