Right Star level
Right colour
Right primary stat
Right secondary stats
...then you need to hope the stat you want gets boosted as you level it...if it doesn't it's in the garbage.
The closest you can come is purchasing from the mod shop and even then only first 4 steps are assured and you're left with a risk of being stuck with something of no practical use.
This. This is the issue.
You could conceivably farm for months or years and never get a great speed secondary because of RNG. That's not likely to happen, but it's entirely possible in the outlier scenario. There will be statistical outliers in both directions. More farming SHOULD alleviate this problem, but that is no guarantee.
There are possible solutions. Many people have suggested many different things. Diminishing returns on speed, diminishing returns on damage based on speed(the faster the toon, the more the damage penalty), etc. Another possible solution could be to make every secondary stat on a mod bump once and only once when leveled, and revert all current mods to that state. Quite possibly none of that would even work.
People with great speed secondaries don't want to hear it, people without them would welcome just about any type of relief.
Speed secondaries make everything else about mods almost irrelevant. On most toons, full sets of +20 or more speed seem to be better than set bonuses and primary stats. If you get the right sets and primaries, that's a bonus. Speed > all for most.
Mods aren't the problem. Mods and character customization are great. The implementation of speed secondaries and the RNG nature of acquiring said secondaries is an issue.