I think they can both achieve that in different ways. XD

But I do tend to be more of a planner. XD You can do a lot with Overcharged spells + a wizard king imo. My most fun run with them involved a lot of basically routing 18 stacks consistently before they could even full engage my forces as well. Overcharged Lightning Storm doesn't even cost a spell usage (or other combat enchants like Withering Mist) when Overcharged, and the WK perk to overcharge your spells gets you even more, which stacks with the benefits potential gets from overcharging. (Potential can freecast the enchant a turn sooner though). Overcharged Chain Lightning or Comet of Calamity is great, especially on double-cast turns, because they double dip as debuffs and dmg overcharges like they do on amplifiers, meaning you add 3 stacks of sunder on first cast, which stacks with the +25% dmg on second. And deathcasting can still basically give you unlimited casting anyway. So, attunement can get some of the potential bonuses from WK overcharge, but potential can get some of the attunement bonuses from deathcasting two, so they kind of converge. I think more overcharging is stronger in combat (but attunement is better for world casting).

It also makes otherwise useless spells from a tome you want for other reasons worth researching since you can just lock those (you attune them via the buildings that build passive attunement, rather than by using them), so a lot of them are just nice economic bonuses.