There should be more mod secondary options so that there is actually an opportunity cost to choosing Speed; also, the existing secondary bonuses (such as health, protection, defense, etc) should be fatter so that there is an opportunity cost in that way too.

Secondary options that should be added are things like Health Steal, Dodge, Accuracy, Crit Avoidance (Crit avoidance is a primary but can't be a secondary as things are now). Make mods better, and make speed less of a necessary mod choice, but fattening the existing secondary bonuses and adding the new ones I've listed. Make the meta even more diverse.