there is a common misconception here, there is nothing wrong with the lightning spear spell OR faith builds for that matter, it's just that faith builds in dark souls 3 need to be approached in a different way than we're used to from ds1/2. In the previous games you just got the spell, the faith to use it and were able to do max damage just by casting the spell, even from far away. Dark souls 3 wants you to approach offensive miracles in a completely different way, if you noticed, talismans were re-introduced in ds3 and have a unique weapon arte called unfaltering prayer that allows you to cast a spell while temporarily increasing your poise and reducing damage taken. It is a fact that offensive miracles benefit greatly if cast RIGHT in front of the enemy (seriously, it increases damage by a LOT). what you want to do in dark souls 3 is pump some stats into vgr/vit to make yourself able to take hits, then into fth/atn for spell casting (just use a fire infused weapon till you get 20/20/20/20 in said stats). once you have the necessary stats (at least 20/20/20/20 mentioned above. i started as a herald and infused my spear with fire, with these stats i'm only lv 46), equip a talisman (preferably the canvas talisman, it has the best damage to poise granted during unfaltering prayer ratio) and (for early game) morne's ring (maybe lloyd's shield/sword ring as well), definitely the sage ring (increased casting speed) and cast your offensive miracle at point blank range by using the unfaltering prayer weapon are (LT). you'll want to make sure to time your spell so that it lands WHILE the enemy is attacking you so they can't dodge. if you got the stats recommended and equipped a decent set of armor with that nice vit, you'll be able to trade blows and take less damage while guaranteeing the spell lands as they can't dodge while in their attacking animation. Early game spells include lightning spear, lightning stake (i plan on getting this soon, if you want to kill the sandworm in smouldering lake to get this spell you wont regret it) and i use heal and replenishment. I use the default herald class shield, but if you want to have both a talisman AND a chime (talisman for offense, chime for hp regen arte and maybe buffing) then feel free. i have a +3 canvas talisman and am able to hit 193 up close with lightning spear, this may not sound like much after having played dark souls 2 where everyone wants AT LEAST 1500 hp mid game, but in dark souls 3 the "must have" amount of hp has changed alongside the way to fight as a cleric. Most people have around 1000 hp early/mid game (if they even have 1000 hp as another thing that has changed is that people tend to dump most of their stats into str/dex for offense) and cap at 27 vgr late game, so i'm able to hit 1/5 their hp (that's while at only 20 fth too) per lightning spear and am able to cast lightning spear 5 time per FP bar WHILE using unfaltering prayer.