Climbing, Directed Spells, Stalking, Swimming at +25, Body Development at +25.
Pure ST maneuvers to pick things up at -20, encumbrance at -20.
Some skills are strongly stat tied (X/X) or (X/X/X) while some are weaker (X/X/Y) (X/Y) or (X/Y/Y).
I suspect the reason for the mixing of stats was an anti powergaming measure to nerf MinMax builds. . .A bricky fighter needs ST and AG for weapons, Co and SD for Hits. A swashbuckling rogue needs ST and AG for Weapons, Qu for dodging. . .making it hard to max one stat vs all others and get a powegamed build out of it. . .if you push to extreme, you either need to really nerf the other 6-7 stats to max 3-4, or moderate your build.
One of the complaints sometimes made about pure casters is the fact that they are the one profession type most suited to going for broke and a max 100-101 realm stat, then to crom with the rest. (Especially Channelers, with an In being handy in play for perception tasks, and few directed spells needing Ag.)