I think that i have the same solutions everyone else does. I have a midleanth 16" for Home Defense, and a longer (18" MK12 Style) for target work and to get a boost in MV. I can for some situations really see the need for short barrels on the AR15, I know that the shorter you go the lower the MV goes, but sometimes the handyness of the system outweights the defects. If it were not for the horrible muzzle blast i would almost consider getting an SBR for home defense, but the combined effects of muzzle blast, paper work and fees just turns me away.
Now having fired both 16", and 14.5" weapons indoors I have to say that its loud and lots of flash but I did not notice the blast myself. (my concern in the future, would be hearing damage to members of my family from a defensive shooting.)
As for sight radius with mid, full, and carbine it does not matter to me. Since I mostly use some sort of optic I use the sight for backup. Even at times when shooting the three I did not notice that I shot any better or worse with oen vs. the other. I know that sometimes the theoretical differance in accuracy from something is midagated by our shooting skill. (or in my case sometimes lack there of!) It would be intresting to have some really good shooters do a study with the differant leanths of sights and then get some stats on what the exact effect is. We all know it does have an effect but how much really, or is it more like the differance between .15 & .20 MOA? I can't shoot that well to notice. just a thought.