We may eventually remove the elemental bolt spell line at level 1 from arcane casters as it may become redundant (exception: chaos bolt will remain)
- Cantrips Scale at 75% spell power.
Unless there's some technical reason to remove elemental bolts, I'd say what's the harm in letting them stay, other than looking like competition to cantrips?
At level 3 let's say you have 80 spellpower and Maximize feat. Metamagic is a bit expensive to use at that point, so keep that always on for the cantrip only.
Maximized Cantrip: 1d6 x 3 x 2.35 = 24.7 avg
Maximized+Empowered Cantrip: 1d6 x 3 x 2.91 = 30.55 avg
Maximized+Mental Toughness Cantrip: 1d8 x 3 x 2.35 = 31.73 avg
vs
standard Elemental Bolt: 1d6+2 x 3 x 1.8 = 29.7 avg
Endfight time and turn maximize on, Elemental Bolt goes to 46.2 avg
Elemental Bolts do however have a longer cooldown (4.5 seconds/3 seconds). They could probably act as cantrips if their cooldown was reduced to the proposed cantrip cooldown. The feat bonuses would then target these spells instead and new such spells would need to be added for the remaining damage types.
Despite stepping on Warlock toes a little, I'd call for cantrips to be toggles to be used for caster autoattacking instead.
The feats improving cantrips will not make the cantrips good, but I guess it's a bonus for anyone already taking the feats regardless. I've personally not been in situations where my builds would ever need to consider them however, and I can't see myself adding them in just to improve very weak spells by 1 average damage per level. Casters are quite feat starved
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Does the addition of these cantrips change existing "cantrip wands"? Some of them even share a spell name with cantrips already.
Eternal wands exist for
Finger of Fire
Ray of Frost
Acid Splash
Spark of Light
Cure Minor Wounds
which are all definitively in "weaker than level 1 spells" category (as well as weaker than the proposed cantrips).
There are also some other low level spell eternal wands, like Magic Missile, Nimbus of Light and Disrupt Undead, with Temple of Elemental Evil offering eternal wands for each of the Elemental Bolts, and the Legendary versions would actually gain a boost with the max caster level increase if their spells are adjusted.
Wands must be held in main hand so they're not ideal equipment for anyone in epic levels as is and so I'd suggest making wands optionally wieldable in offhand, and the act of casting a spell on an offhand wand to become a new autogranted feat akin to Attack (but not a toggle).
And be compatible with Single Weapon Fighting/Swashbuckling. Do you think this would step on toes of Rune Arms though?
Of course wands are still a bit obsolete for damage due to spellpower scaling issues (as in, they don't, and they probably should).