Mouseover or click of some INFO columns such as Power, negative Weight, radar chance could give an explanatory tooltip.
Search for a column by name, e.g. if you want to know what kneel modifier in Defaults is it can be hard to scroll.
Arguably weapons should default to including the stats of their ammo if they only have one compatible ammo.
UFOpaedia remembers your previous runs, or option to have all combat analyses unlocked so you know why you're dealing zero damage.
Combat analysis -ish pages with TU, accuracy, etc. Hard to tell how good a unit is without. Many modders manually list this for player units.
Just like you can alt-hover to see weapon damage, ctrl-alt-hover to see that number * the number of shots you can take this turn with remaining TUs and ammo, so you have a closer approximation of "DPS".
Diablo-esque item comparison or sortable spreadsheets if you're crazy enough to implement either of those.
Option to list "NONE" for a ruleset image in which case it uses a blank one, or to reference placeholders that might not necessarily be the perfect size.