Also cannot recall seeing any spear weapons that I thought were particularly amazing. I have yet to hear of anyone outside of a mod situation opt for a serious spear wielder. Overall, in tandem with heavier armor, STR tends to win out here. Could definitely see some more chances for cross-skill tree support here to help better define the identity of a spear wielding polymorpher, as well as allow for a more interesting set of build combinations. Seems like an opportunity miss here, as we all know from other games the Spear Thrower + Shield (Commander/Paragon) archetype that might utilize Huntsman and Deadly Savage (Druid/Feralan) archetype that might utilize Scoundrel. Spears have very little synergy with damage skills from the primary FIN-trees, Scoundrel and Hunstman. Works for either STR or FIN (and INT for stave weapons). Most Warfare skills scale with whatever your melee weapon's primary stat is. If you had to choose based on this factor alone, go with STR-gear.
I believe only a few Polymorph skills scale with FIN otherwise, it's STR. If you really love spears then great otherwise, you'll find a lot more STR-based weapon options: 1H + Shield, Dual Wield 1H, and lots of 2H weapons. This is because spear weapons are FIN-based. I guess the spear allows for more crit power? Everything seems to scale to strength. I still don't understand why they're a finness class though, according to metamorph.