they probably think that casting three spells that make 20 damage without needing to pierce armor is OP and people will always do that if they'll have enough mana. but they could just lower the damage while making casting faster. remove attacking spells that are very powerful, while making weak ones weaker to accommodate for always hitting for a specified number. then make EVERYTHING cost less mana and you having more mana at the same time. that at least will make the magic useful, currently I find it useless.
Even evasion spell is worse than just blocking with shield because it costs mana and you don't have enough without being a full mage that has huge Magic stat. And even recently nerfed Spring Attack is a better way to inflict bleeding and damage opponent than wasting turns to cast inflict wounds for a crazy mana cost and no additional damage.
in any case, it's a porn game, so its combat should not be that tricky. that's why making physical stats not OP probably isn't a great idea. people won't beat the game. Only if there will be something like Master difficulty with tweaked stats, or if there will be a completely different game. also they really try to make you use other skills, but they do that by making good skills worse, not by making you interested in any of the huge amount of other skills. who would seriously try attacking wrist, for example, even if there's a mechanic to eventually make them lose a weapon. or attacking head.