Whether you like mana regen or not, it is such a difficult thing to balance across all levels and skills. Consider the factors in setting a base mana regen:
- Cooldowns exist for some skills not others
- Some skills cost health instead of mana
- Some builds spam skills indirectly, via minions
- Some players want 5 active skills, others use 1 or none
- Some active skills chain with others, other active skills synergise with nothing else.
- Some builds and classes are inherently tanky, while others are glass cannon
- Early game mana items need to be weak, end game items need to be strong
- Enemies provide a variety of situations to deal with. Some are high damage, low health. Some are ridiculously high health, some are swarms, some are continuous swarms, some have phases, some are invulnerable, most have an AOE clear the screen ability of death which means players must stand in a particular spot to stay alive.
- Some skills have mana reduction choices, some do not.
Now if you get the balance ‘wrong’ because you have too many plates in the air to ever get it ‘right’, you get legitimate critiques of the system as found in this thread:
- A whole lot of skills are now gated by cooldowns and mana, so players just stand around and wait, which does feels bad
- A build which can use health instead of mana gets a huge advantage over the mana builds. Do we now nerf the health cost builds to oblivion? Do we really have time to check health costs, life regen, leech when we change a number for mana regen?
- A low damage, many cast build (say applying poisons via hungering souls) now has mana to manage, so now has no stat slots for either damage or defence, so becomes unappealing vs having, say skeleton mages apply the poison for you. Both builds become F-tier vs end game content because your clear speed either becomes ungodly slow, or your skeletons get wiped en masse. (In 3 years of acolyte builds, show me one that uses the poison nodes on skeleton mages or hungering souls… in fact, show me more than one that does not scale crit as it’s damage source)
- Having 5 active skills becomes impossible, so whole creative skills trees, and creative chain skill interactions disappear - players focus on raw stats and power for just one skill because that’s all they have mana to cast.
- Builds end up being pidgeonholed into certain item/stat combos. If you are playing thorn totems right now (and who is?) you must have 2 mana items equipped, and have 30 points in shaman mastery’s attunement and mana regen. No viable alternatives exist.
- The gap between the rich and poor, the elite and casual becomes incredibly wide. Got sweet gear and wiling to grind for days to get blessings, etc.? OK, you can build pure damage nodes on the skill tree and face end game content that relentlessly sends high HP enemies at you that need huge amounts of mana to kill. Playing casually? OK, you will need to find enough low tier mana items on gear, and invest enough in mana efficiency on the skill tree to even cast your stuff. This will mean your damage feels terrible, and your grind to your next mission, boss, etc takes 3 times as long…
- Some skills now get nerfed to oblivion by just a small numerical adjustment. Were you previously spamming an AOE skill? If you previously missed a mob, that’s OK, you have the mana to cast again. Now if you miss a mob, you cannot cast again for 2 seconds, and the mob swarms you.
The same issue arises with life leech, as addressed in this old post.
The end result is that game directors and management have a well meaning brainstorm about the direction of a game - “Mana will be a resource players care about!”. Yet it won’t matter how much checking is done, the rollout of the seemingly simple change will feel like that familiar cycle of random huge buff/nerfs and the only way to achieve some sort of balance will be endless power creep, graveyards full of potentially creative skills and items, forums dedicated to trolls instead of build ideas, and bandaid adjustments - which POE players will be familiar with.