Super Training was garbage. SOS battles are the best way of EV training know and even then Poke Pelago allows you to EV training multiple Pokemon while you sleep. Dex Nav was cool, but SOS Battles also let's you get HA Pokemon and increases Shiny chances, Fiend Safari is Missed I'll give you that.
SOS battles are right up there as one of the worst battle types in the series to me, only surpassed in awfulness by Sky Battles.