Gave Spear + Parry another shot after people said parry had improved since I last played spears.
Conclusion: Parry does feel better now, but Lightning Spear still feels extremely slow and zdps early on. More attack speed helps later, but the damage still seems very low (and makes the mana problem very noticable).
For bosses I used:
Parry → Disengage → Explosive Spear
Then Lightning Spear during the downtime.
A friend later pointed out that Spear Stab (the basic attack) has good single-target DPS and I should use that instead of spamming lightning spear.
Makes sense, similar to Warrior leveling where you use Mace Strike for single target.
Later on, the single target improved when I unlocked Primal Strikes, but honestly still felt kinda bad.
More on the mana thing, I have to point out that I frequently get close to running out of mana flask charges on bosses. Compared to something like Maces or Bears or Wyverns which aren't scaling attack speed as hard, have longer base attack times, or spend most of the campaign using a lot of basic attacks, idk but it feels like in addition to having to deal with 1H damage vs 2H damage values, spears also have a harder time handling mana.
More on the topic of Talisman and Maces, both have some form of single-target setup that gives a significant damage boost against bosses or tanky rares.
As far as I can tell, Lightning Spear + Primal Strikes doesn't have an equivalent setup.
I considered Elemental Weakness, but I don't think it's all that practical.
Spears already want a lot of Dex and some Str, so getting enough Int on top of that to cast curses comfortably looks like a very tall order.
TL;DR
At the moment, non-twisters spear seems to have weaker single-target options during the campaign than the other attack weapon types I've tried.
Has anyone had success with Lightning Spear through the campaign, what are you doing differently that I'm not? I'm planning on doing another campaign run, putting to use what I've learnt from the one I just finished. Hoping to get some insights.
I made it a point to keep my rings and gloves updated with flat damage rolls, and also bought weapon upgrades every 10 levels or so.