As I see it, that's another reason why strike craft are horrible: In order to acquire H slots, you'll be trading away L slots.
This wouldn't necessarily be a problem if these were of equivalent value, but you're also getting S and P slots in the trade - which aren't always attractive.
This has at least been partially made up for now in 2.2, where point defense weapons are insane knife-fight range guns that punch far harder than any other 's' slot, at the cost of vastly reduced range.
Seriously, if I get t2 point defense early, I think the point defense corvette becomes the best design because that guardian turret deals twice the dps of a t2 laser or kinetic. And I only need to slap two lasers on it to burn down the armor for it to remain at peak effectiveness.