That's all well and good, and this debate will undoubtedly stretch into the next century. I'll stick with a target load of 7�'s indoors because the aforementioned reasons of faster follow-up shots, if necessary, allowed for by less recoil. Attenuated muzzle blast provided by a magnum in close quarters is not to be overlooked also.
So what if none of my shot completely penetrates an attacker's torso? He is going to be one sick sunuvabitch if not altogether down for the count. In addition, if the gun/load will be employed by a household member who is not fond of guns and shooting, instilling a level of proficiency in them through practice with the defense gun will be worlds easier with "mild" target loads. Use of those same loads by that person in a self defense situation will have a much more telling effect than a magnum load delivered by someone shaking from fright and squeezing their eyes shut in anticipation of the recoil and muzzle blast.
In short, in a tense do-or-die situation I'll go with controlability over extra force. Better to hit him square in the face or chest with a target load than to come close with a magnum turkey or buckshot load.
