In having a solid connection with uke proper speed should take care of itself. The speed of the application of technique will be dependant on the energy provided by uke.
My teacher often reminds us "Don't do the technique by yourself..." ie. too fast, or rather, so fast you lose connection with uke.
Speed,I would imagine, comes down to practising with a partner who is sufficiently advanced to offer you the kind of energy that decrees you move quickly. This kind of training is no more or less important than training with the total newbie and having to move in slo-mo, it's just different.
Both of these kinds of training can help you gain a proper grounding in basic movement.
Merry Christmas all,