That set can be pretty good, but it is still inferior to the normal Ninjask SD set. The first reason why this set is outclassed is because the SD set has no survivability. Ninjask can have several chances to switch in, and this set is just ridding you of a lot of health for a small attack boost. And that leads me to the second reason. Your set only works once for a small attack boost, whereas the SD set, as I said, can come in and set up multiple boosts at different times in the match.
One thing that can make this set different is the adding of a petaya berry, making it a set-up pokemon for a special sweeper. However, Volbeat can pass bigger Satk boosts and can come in more than once. But, although Ninjask can only pass one Satk boost once, it also passes speed, turning pokemon like Samurott into unstoppable monsters.
To sum it all up, I say that speed boost + leichi berry is outclassed, and a better choice would be petaya + speed boost, if you don't mind a lower Satk boost compared to using Volbeat.
Also, flash is just... don't use flash...