A 30-30 improved doesn't make a whole lot of sense to me.
Heck, none of the "improved" cartridges make any sense to me. I mean if I wanted or needed more power and velocity than "X" cartridge offered then I would simply purchase the next larger cartridge instead.
I agree with nyorange in that the regular 30-30 is plenty enough gun for deer to about 200 yards. With iron sights on this gun what exactly would be the point? Can you shoot these iron sights well enough to take advantage of the extra couple hundred FPS? Which at 200 yards the trajectory differance would only be about 2 or 3 inches.