When starting new games, I find myself constantly miffed by missions that require 100 units of deliverables; the Cerberus and Shepherd both top out at exactly 100. While it's interesting in that it encourages you to use the overload mechanic, I find it a little weird that a load quantity that is specifically very difficult for standard 'tramp freighters' should be common amongst mission-issuers. Maybe it's Tri-Tachyon corporate rules?
Notably, this means that these ships have no missions advantage over a Hound or Mudskipper (75 cargo each), as both of those can just as easily conduct 10- and 50-unit missions.
Similarly, freight range for destroyer+ cargo vessels ranges from 250-450, with 300 being the benchmark quantity for Tarsus and Buffalo freighters. But missions for 500 are common for the 'mid range but achievable' cargo amounts.
This isn't a problem really, but IMO either missions or ship cargo quantities should be structured around each other.
FAKE EDIT:
Actually, this gives me an idea. Perhaps the unit size for each faction's missions should be based off of their commonly-used cargo vessels, or off fixed values defined by the faction. For example, a faction that commonly used Cerberus (cargo size 100) and Gemini freighters (cargo size 250) would typically issue missions for ~80 and ~210 units. But a faction that used Hounds and Tarsus freighters would issue missions for ~60 and ~250 units
Then you'd have the super-sized missions on top of that, for the truely ambitious freight convoy.