[Kromm]

I've never seen it as a "big" thing. I've run GURPS for years, and whether the relevant skill was called Innate Attack, Magic Breath, Magic Jet, or Spell Throwing, it was Easy. Whether the skill progression was {1/2, 1, 2, 4, 8, +8} or {1, 2, 4, 8, +4}, it was centered on DX at 1 point, and it was the rare wizard who bothered to spend more than 2-4 points on it anyway.

Casters who wanted to be warrior-wizards generally started with good DX, like all warriors. Not as good as that of a dedicated warrior, but that's fair; when doing two things at once, you advance half as fast. Warrior-wizards were expected – fairly, I think – to spend the points to compete in combat. As is, they were privileged with Easy skills; archers had to learn a Hard skill prior to Fourth Edition, when Bow became Average, while melee fighters have always had to learn an Average skill for typical battlefield weapons. On the other hand, non-wizardly warriors didn't spend FP or have casting times.

It all seemed pretty balanced over the years.

So I wouldn't want to go too far in the direction of making the more physical kinds of spells easier to hit with. As others have pointed out, there's a perk for that, called Psychic Guidance. In effect, it's an Extra Option perk that flips a switch: "Knowledge of spells includes knowledge of hitting things with spells." The GM could always waive the perk and go with that as a campaign-wide assumption, but I think it better to associate some cost, at least a small one, with enhanced ability to hit – whether that's Psychic Guidance or the Innate Attack skill.