There is also a setting to control the random variants it chooses. Click the filter/funnel icon in the top-middle of page, in the main toolbar. Under "Other Filters" is a "Random Variant Mode" option. There are three options:
Any - allow any variant
Exclude Single Stat - don't allow variants with a single secondary stat
Only Two Equal Stats - only choose variants with two secondary stats, and equal amounts of those stats
Most crafted items have 46 variations. The chance of getting e.g. a crit/haste variation is 7 out of 46. Those 7 variations range from low crit/high haste to high crit/low haste.
You have a 1 in 46 chance of getting the single-stat variants.
If you choose the "only two equal stats" option, that is a decent option to sort of approximate how valuable any crafted item you might get would be.