have them spawn with things like average damage, crit chance, and attack speed
Why? They have single target main attacks and their DPS doesn't scale well enough to justify offensive mods anyways.
Let me correct this common misconception.
Take the enchantress.
Her spam is indeed nerfed to only do 20% damage, like all follower spam.
But, the two damage skills you teach them do FULL DAMAGE, they scale with their weapon damage and primary stat EXACTLY AS OUR HERO'S DO.
My 'chantress has 4192 intel right now, she uses a 1368.8 dps weapon, she has 19% cc, she has 496% cd.
Her AoE forceful push can crit for over 500k on a 10 sec cooldown and is the first skill she will use on meeting any monsters, interrupting any charge attack.
Her AoE erosion DoT can crit for ~300k per tick, 5 ticks, and puts a '+15% damage taken' debuff on any mob it hits, on a 15 sec cooldown.
Those 2 skills together mean she is constantly AoEing, interrupting and debuffing the hell out of mobs.
She kills goblins solo in low MP's (and why would we farm higher MP's anyway?), she clears any mobs out of my range as a melee, she finds me legendary items daily, she protects me if I should go afk by blowing up anything that comes near. She can solo all bosses on low MP (except Diablo, she sux at avoiding traps).
I have ported to a WP before and had a legendary item waiting for me before my character even loaded.
People use the 2 crowd control skills which are on 25 sec cooldowns when forceful push alone not only does massive damage, is only on 10 sec cooldown, but in fact has with it a crowd control and interrupt, in that monsters will turn to her and emote (if they live), controlling them for as long as the crowd control skills would anyway.
Take your dps gear off your character and replace it with low dps MF and see how useless you are, take non damage skills and see your dps drop. It is the very same principle.
Enchantress is a very efficient ranged AoE dps and support for melee, immensely helped with crit.
Scoundrel is a very efficient single (or 3) target ranged dps and support, immensely helped with IAS and crit.
Templar can have 78% block, 30%+ dodge and massive EHP. His lack of threat and therefore role as a tank however should be addressed.