While Psi Strength/Skill is what counts when developing a soldier's stats, in Battlescape it's Psi Attack/Defence that matters. From what I've read on ufopaedia.org, Psi Attack is PST × PSK ÷ 50, while Psi Defence is PST + ( PSK ÷ 5 ). I guess soldier stat screen is too full to add additional stat types, but it would be nice if we could at least sort soldiers by Psi Attack/Defence in the base soldier/craft load screen combobox and see the numbers in the sort column, to help with picking solider loadout. Right now I keep a calculator nearby (which I use for TU crunching anyway) and keep mental note when sorting soldiers. Not too bad when you still have a handful of Psi troops, but gets difficult when Psi numbers swell.
Also would not be as important late game when you're filtering soldiers to >90 PST meaning you can just pay attention to PSK, but would be super helpful early to mid game when PST is quite varied, and PSK is still developing ranging from 16 to 100. Hard to tell at a glance if a solder with high PST might still have low PSK, so for a mission you might prefer a middling PST soldier with already high PSK in order to guarantee MC instead.