It's difficult to compare design/performance of damper portion based on physical size alone because the Safe-T-Plus encapsulates the spring inside the tube, making it much larger regardless. If spring(s) were outside like on other models (one shown below for comparison), the damper part would likely seem much smaller.
Also, damping force isn't tied directly to the diameter of the damper because they can have different valving which can create higher or lower internal pressure to accomplish the same performance. Ford may choose to make theirs smaller and of higher quality to save weight, or for other reasons. Smaller doesn't necessarily mean it's weaker.
Please note I'm aware that while these dampers are similar to shock absorbers, they don't need to dissipate the same amount of energy, so being larger like shocks doesn't have an equivalent benefit. Just saying that from an engineering standpoint, we can't go by size alone.
In my opinion the spring portion is where the discussion gets complicated and controversial. I would just suggest asking yourselves why truck (or car) manufacturers don't include spring centering devices from the factory.
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