when you let them be better than class spells then it raises a question of "Why is a rogue able to cast a better damage spell than a pure sorc gets in his spellbook" It undermines your class identity and then your class doesn't matter for anything besides how many caster levels and crit chance they give your epic spells and whether your class can get rid of immunity for your epic spells. Epic Strikes mostly fit the role of rotational filler to fill out gaps from your regular spellbook
This reasoning isn't a problem. A rogue isn't going to have more spellpower or spell crit than a caster who has invested a plethora of resources in that, so the spell epic strike will be better for sorc. No a problem if the strike is better than spells the sorc. Heroic spells should be compared with regular attacls of the weapon users.
But if this were really a problem, then what needs to be done is remove SLAs from being based on character level and make them work on caster level, so they're class-agnostic spells that accept any caster level. And for the rest, set a minimum caster level so the weapon users have some use for this (caster level min, decide according to the most balanced). Done, now only casters can get the maximum power of the strikes, and the rest can have a more basic use of them.
This is actually what happens with heroic spells. In 3ed pnp, cone of cold, for example, can only be cast with a minimum caster level of 9 because that's the minimum for casting a 5th-level spell. Casters learn to do this better as they level up, until they reach the MCL. Epic spells should also have a minimum CL, so it's possible to play with this concept so that casters can use them at a higher CL than someone who isn't trained in spellcasting (or who has only had partial training for a few caster levels).
Caster strikes should NOT be weaker than spells if weapon strikes are, as they are now, stronger than their special heroic attacks.
The developers would save themselves a lot of trouble if they respected the original rules more instead of breaking them at will.
As an aside though, the r7+ spell damage penalty either needs to be the standard for everyone or scrapped, it hits everything except front number damage so even imbue and proc focused builds are hit by it
This is true. Or the nerf is universal, o rit needs go away. One thing or the other,