This seems like a possible call to the "specific trumps general" rule.
The rule that touching an unwilling target for is accomplished by making an unarmed attack is the general rule for a touch-range spell. However, indirect combat spells (specifically) use the specified rule that hitting the target is accomplished through the spellcasting test.
OR Aaron's suggestion was an attempt at simplifying things. Since the Spellcasting Test is already opposed by the same thing that the unarmed attack would have been, eliminating one of the redundant attacks seems reasonable. We don't want to eliminate the Spellcasting test, so the clear candidate for elimination is the extra initial to-hit roll.
Personally, I think that works just fine. Technically, because it is an indirect spell, the caster doesn't even really need to make complete contact in the same way that you would with a direct spell. When you cast the Punch spell, it's going to go off no matter what you end up touching. As the spell says, you "smack the target(s) with invisible psychokinetic force." That force is being set off, whether you hit or not. Just, with the Punch spell, the target has to be close enough to touch...
